Sandslash is a Pokemon riddled with very exploitable weaknesses. With pitiful Speed and Special Defense stats, as well as a rather small offensive movepool, it's completely natural to reject the idea of using Sandslash in OU initially. However, with its Dream World ability—Sand Rush—Sandslash becomes a notable threat in the OU metagame. Being a Ground-type, Sandslash has access to a decent movepool, passable bulk on the physical side, and nearly impeccable coverage in the celebrated EdgeQuake combination. Moreover, Sandslash's access to Rapid Spin allows it to serve as a fearsome offensive Rapid Spinner for Sand teams. Sandslash's movepool, notably Swords Dance and Rapid Spin, gives it strong reasons to be used over the faster and bulkier Stoutland, who also has access to Sand Rush.
Despite all of its mentioned perks, Sandslash is by no means invincible. There are many, many Pokemon that can place Sandslash in a tight situation, usually through means of harping on its average offenses, feeble Special Defense stat, and / or inability to outpace a few notable threats after a Sand Rush boost. Additionally, Sandslash is much less of a team player than other Pokemon, as changing the weather makes it very slow and vulnerable. Proper team support and, more importantly, patience, are necessary when using Sandslash.
Sandslash can pull off a Swords Dance set similar in playstyle to Excadrill's to great success. After the activation of Sand Rush, Sandslash can reach a Speed stat as high as 502, giving it the ability to easily outpace and subsequently KO many of the more offensively oriented Pokemon in OU. The above choice of moves is ideal for Sandslash if it's to be used in OU. Swords Dance quickly boosts Sandslash's Attack stat to threatening levels. When backed by a Swords Dance boost, Sandslash is even capable of powering through some of OU's premier walls, which is something that Stoutland occasionally struggles with. Earthquake, being Sandslash's strongest STAB option, is capable of blasting through many of OU's grounded inhabitants while Stone Edge nails most of what resists or is immune to Earthquake. Rapid Spin helps Sandslash maintain pressure on more defensive teams and gives it the ability to greatly support its own team; however, X-Scissor lets Sandslash power through bulky Psychic-types that take little or no damage from Earthquake, such as Celebi and Latias. Make the moveset choices which best accommodate your team.
The recommended EV spread is one that aims to simply give Sandslash as much speed and power as possible. With a Jolly nature, Sandslash outpaces the majority of the metagame under sand, including Choice Scarf Garchomp and everything slower. A Jolly nature also enables Sandslash to serve as a potent revenge killer, KOing threats such as Scarf Thundurus-T, as well as Volcarona after a Quiver Dance, and Salamence, Dragonite, and Gyarados after a Dragon Dance. However, do note that Stealth Rock will be necessary for some of these KOs. Using an Adamant nature on this set is a perfectly acceptable choice, as it allows Sandslash to serve as a superior Rapid Spinner. For example, a +2 Earthquake from Adamant Sandslash will almost always KO Jellicent after Stealth Rock, while Jolly Sandslash will fail to do so most of the time. Just beware that with an Adamant nature, Sandslash's revenge-killing capabilities will be severely handicapped, as it will be outsped by Choice Scarf Landorus-T and everything faster.Team Options & Additional Comments >>>
Unfortunately for Sandslash, its movepool is pretty dry, leaving it very few options to use. Sandslash can use Rock Slide over Stone Edge for a more reliable Rock-type attack, but Rock Slide's lower power often means it will fail to OHKO many of the threats it would be used against. Thundurus-T, for example, is KOed handily by Stone Edge, while Rock Slide requires it to have taken Stealth Rock damage. Dragonite and Salamence, two prominent sweepers, can be OHKOed by Stone Edge after Stealth Rock, but not by Rock Slide. With access to Stealth Rock, Super Fang, and Rapid Spin, Sandslash is capable of running a defensive set. However, Sandslash's terrible bulk on the special side often makes such a set difficult to run. Additionally, Donphan is able to run almost the same set, but with more bulk, more power, and the utility of Roar. Because of these factors, Sandslash is poorly suited for such a set.
All of Sandslash's good move options have already been discussed, but its movepool goes on. Night Slash can be used for a super effective hit against Gengar when Sandslash lacks any boosts, but a +2 Stone Edge already does more than enough damage to quickly dispose of it. As far as other items go, Sandslash can use Soft Sand to power up its already strong Earthquake without the recoil of Life Orb. However, Sandslash's middling Attack stat once again rears its ugly head, and Stone Edge will find itself missing KOs without the power boost of Life Orb. Lum Berry is the only other item worth considering. It allows Sandslash to set up a Swords Dance on Jirachi without worrying about paralysis, and means that specially defensive Sableye can no longer beat Sandslash. Unfortunately, most other status-spreaders, including Jellicent and specially defensive Heatran, are still able to defeat Sandslash by taking advantage of its other weaknesses.
Checks and Counters
Foremost, changing the weather will effectively neuter Sandslash, quickly changing it into a slow, minor threat. Physical walls and sponges obviously work very well against Sandslash. Gliscor, Skarmory, bulky Rotom-W, and Landorus-T are just some examples of Pokemon that can place Sandslash in a sticky situation. Although Breloom is not particularly bulky, it's resistances to Earthquake and Stone Edge make it a great choice to combat Sandslash, and it can retaliate with Bullet Seed or Spore. Sandslash also has some excellent counters in the lower tiers. Slowbro, Tangrowth, and Bronzong are able to tank hits from Sandslash all day and bring it down. It's also worth noting that Sandslash, while extremely fast in a sandstorm, can still be outpaced by a small portion of OU, namely Choice Scarf Latios and Choice Scarf Keldeo, and get OHKOed by the appropriate move. Though some physically based Choice Scarf users, such as Terrakion, are able to outspeed Sandslash, they must be careful because Sandslash can survive a hit and OHKO them in return if it is above 70%. Priority attacks are also useful for stopping a Sandslash sweep, but Sandslash's physical bulk means that it can shrug most of them off, the exceptions being Mamoswine, Choice Band Scizor, Choice Band Dragonite, and Azumarill, and even these fail to KO Sandslash from full health. In the end, checking Sandslash will boil down to exploiting its mediocre offensive stats. Don't be intimidated by Sandslash's Speed stat as, with the appropriate Pokemon, it can be swiftly brought down through calm and intelligent play.