Armaldo is one of those Pokemon who seems to try to do too much with just too little a stat total. It can be defensive or offensive, but not both, with the result that it is often all too easily discarded in favor of more specialized options. On the defensive side, it has just two resistances to rarely seen attacking types, a weakness to Stealth Rock, and a lack of reliable recovery. On the offensive side, Armaldo's horrible Speed comes back to haunt it with a resounding clang. Even past that, there are many who feel that Rhyperior can do everything that Armaldo does better, and with good reason. Unlike Armaldo, Rhyperior has no Stealth Rock weakness, a higher Attack stat, and STAB Earthquake, while also having access to Megahorn, which is more powerful than Armaldo's STAB X-Scissor, as well as Solid Rock to compensate for its higher slew of weaknesses.
However, one should not put down Armaldo all that quickly. It has a fantastic support movepool that can be used in all sorts of situations, and it still has its powerful Attack stat, backed up by useful boosting moves and an excellent offensive STAB combination. And make no mistake, it has its own advantages over Rhyperior, most importantly a lack of quadruple weaknesses, making it less easily revenge killed, as well as higher Special Defense and Speed stats, allowing it to outspeed both Milotic and opposing Rhyperior. All in all, it has to be said that Armaldo is, whatever its shortcomings, a powerful Pokemon with acceptable defensive stats and a good movepool, so don't take this arthropod too lightly.
Armaldo returns for another bout of carnage in DPP with little change as far as the basic idea behind it goes: attempt to sweep, or support, but not both. This set is the most ambiguous of all its potential sets to identify in this context—while Rock Polish constitutes a straightforward sweep and the support variant is so named for obvious reasons, this Armaldo can attempt to sweep slower or weakened teams, as well as punch holes in the walls of the opponent's team, thus supporting its own team. It can therefore modify its game to suit any opponent, not only making it the most easily adaptable of Armaldo's sets, but often the most profitable when used competitively.
Swords Dance is naturally the most important move on this set, boosting Armaldo's Attack as far as it can go in preparation for a sweep. After Armaldo has set up, you can show off its excellent STAB moves. Stone Edge and X-Scissor are both decently powered and provide a wide range of coverage together, resisted only by Fighting- and Steel-types. Earthquake is placed in the final slot to deal with Steel-types, as well as Toxicroak and Nidoking, and it is Armaldo's best bet against Fighting-types such as Primeape and Hitmontop. Between these three moves is a conglomeration of EdgeQuake and Bug-type STAB that hits every Pokemon in the game for at least neutral damage.Team Options & Additional Comments >>>
This set is far more concentrated upon sweeping, and getting the job done, than simply going for as much power as possible. Rock Polish allows Armaldo to boost its Speed to respectable levels at the cost of a moveslot that could have been used for Swords Dance, thus allowing it to outpace and hopefully run through the opponent's team. This set should be played in a similar fashion to Rock Polish Rhyperior, with the difference being that Armaldo has STAB X-Scissor and Stone Edge with Earthquake for coverage, while Rhyperior has STAB Earthquake and Stone Edge with Megahorn for coverage. Armaldo also has slightly higher initial Speed to compete with Rhyperior's extra attacking power, which means that it can afford to run an Adamant nature and still outpace Alakazam and Dugtrio after a Rock Polish, which is a massive plus.Team Options & Additional Comments >>>
Armaldo has the potential to support its teammates rather than rely on them for a sweeping opportunity, by virtue of its excellent support movepool. One would expect that, with the many ways it can support its team, coupled onto its reasonable defensive stats, and lack of Speed making it a less potent offensive threat than it could be, this would be Armaldo's most used set. However, its typing gives Armaldo a mere two resistances, to Normal- and Poison-type moves, widely accepted as the worst attacking types outside of STAB, and with weaknesses to Rock-, Water-, and Steel-type moves, which is incredibly detrimental. The Rock-type weakness is really the killer, whereby Armaldo obtains the infamous 'Cloyster syndrome' (being a Rapid Spin user weak to Stealth Rock), and this weakness both limits its survivability and also undercuts its utility as a Rapid Spin user. However, this should not discourage you from using Support Armaldo, as it can be a very useful tool when a lot of jobs need doing.
Rock Slide is advised as your attacking option for reliability, though there are always other options. Rock Blast may seem an odd choice when Stone Edge and Rock Slide are available, but it can also be used to support the team in a way Armaldo's other STAB moves cannot. Similar to Marowak's Bonemerang, Rock Blast can be used to break Substitutes; for example, against a Substitute + Toxic Moltres, Armaldo can break the Substitute with its first Rock Blast, then follow it up with up to four more 4x super effective STAB hits. Its accuracy is shaky at best, but then again Stone Edge has the same accuracy anyway. Stealth Rock is, naturally, a useful entry hazard with which to build up damage, and can be useful if you have no other Pokemon on your team capable of setting it up. Rapid Spin removes the entry hazards on your side of the field, which is beneficial to those Pokemon that have to keep switching, as well as those that are vulnerable to entry hazards, including Armaldo itself. Knock Off is best used by removing the item from more specialized Pokemon—walls such as Slowbro hate to lose their Leftovers, and sweepers will also miss the extra kick from their Life Orb or Choice item. Lastly, Toxic can go over either of the previous moves, its main use being to cripple walls, as well as Spiritomb that attempt to block Armaldo's Rapid Spin attempts.Team Options & Additional Comments >>>
There is rarely an offensive Pokemon who cannot in theory run a viable Choice set, and Armaldo is no exception to the rule. A Choice Band allows Armaldo to hit hard right off the bat, which can be handy since the Swords Dance variant can often be forced out before it has had the chance to wreak havoc, thanks to everything vaguely popular being able to outspeed it. This set gives Armaldo the opportunity to hit its switch-in with a very painful, boosted attack. The downside to this is, of course, that Armaldo loses the ability to change moves, and so a misprediction can be a fatal mistake. Armaldo has a real potential to get stuck on the wrong move, as its STAB moves do not have a great deal of neutral coverage individually. Even then, if Armaldo uses Stone Edge on the switch and nails Moltres, expecting an X-Scissor, Pokemon such as Torterra then essentially get a free turn on Armaldo, which can be terminal to your chances in the battle if you don't have a way to stop them.
The first three moves should be self-explanatory: a three slot combination that hits every Pokemon in the game for at least neutral damage. The fourth move is somewhat of a filler option, and does not really affect your battle chances should you leave the house with one but not the other. Aqua Tail, as demonstrated by Tyranitar in OU, is a good move with which to defeat its counters, Hippowdon and Gliscor, who are indifferent to its other moves and can generally wall the tar out of it, literally. Armaldo would no doubt put this to good use if either Gliscor or Hippowdon were allowed in UU, or if you intend to use this in OU. In a normal UU context, it is only really useful for Donphan, Rhyperior, and the odd Gligar or Hippopotas. All other Pokemon mostly take higher damage from its other moves. Superpower is a more powerful attack than Earthquake to use against Steel-types, though its coverage is somewhat redundant, but because it is as powerful as STAB X-Scissor when hitting for neutral damage, it is worth consideration.Team Options & Additional Comments >>>
As far as physical options go, Rock Slide is available if you want more accuracy than Stone Edge and Rock Blast, Superpower is more powerful than Earthquake initially but has a disadvantageous side-effect, and Cross Poison has completely redundant coverage with X-Scissor. Curse is a pretty useful boosting move, especially considering that sandstorm boosts Armaldo's Special Defense and as such allows it to be surprisingly bulky. However, Cradily does that sort of set much better thanks to Suction Cups and Recover, despite Armaldo's higher Attack stat. For Armaldo, Rock Polish or Swords Dance outclasses Curse as a boosting move anyway. Screech may force switches, and can be useful on a team with Spikes support. Brick Break is also available, more for its utility than its power.
Armaldo has a more-or-less decent base 70 Special Attack, which would make a gimmick mixed sweeper set possible if it wasn't for the absence of nearly any sort of decent special move, the most remarkable of which is Earth Power. Lastly, Substitute is always available to scout out switches and enable Armaldo to hit the switch-in with the appropriate attack, in a similar vein to the infamous Substitute Rhyperior. However, Stealth Rock means that Armaldo is unlikely to have all that much HP to spare, so unless you are running a Rapid Spin user, it is generally not worth it.
Checks and Counters
In general, Armaldo's worst enemy is its own poor Speed. Failing to outrun such a wide range of Pokemon hinders its ability to sweep and forces it to switch out on Pokemon it could otherwise KO, such as Blaziken. In general, however, finding a semi-solid counter to the set depends largely on discovering the set. After this, it is not too difficult to stop with the appropriate Pokemon. Hitmontop is probably the best universal counter, having decent defensive stats, resistances to both of Armaldo's STAB moves, and Intimidate, as well as a range of moves with which to defeat Armaldo, such as Close Combat and Bullet Punch. Hariyama has the same resistances, is also quite defensive, and can beat down Armaldo with STAB Fighting-type attacks.
Once Armaldo has gotten a Swords Dance in, the best option is really to revenge kill with a faster Pokemon. In terms of bulkier Pokemon, Weezing can take a +2 Stone Edge and burn Armaldo with Will-O-Wisp, while Steelix and Rhyperior can easily take a hit and attack back with their respective STAB moves. For the Rock Polish set, the list of paper counters extends much further, where reasonably defensive Pokemon such as Registeel and Milotic can all effectively take on Armaldo.