When one looks at Escavalier, one draws obvious comparisons to the more established physical Bug- / Steel-type Scizor. While it is true that Scizor overshadows it to an extent, to dismiss Escavalier outright is a mistake. Sporting a base 135 Attack stat, it is the strongest physically offensive Bug-type, beating Scizor by five points, whilst also tying for strongest physical Steel-type, next to Metagross. With 70 / 105 / 105 defenses, Escavalier is actually better suited than Scizor for absorbing both physical and special hits, and can hit back hard with STAB Megahorn, which, when paired with Choice Band, has the ability to 2HKO Hippowdon and Suicune.
In spite of these strong points, there are reasons why the jolly old cavalier is overshadowed by Scizor. Base 20 Speed is absolutely horrid in a fast-paced metagame, and the detriment of this weakness is compounded by Escavalier's lack of priority attacks or Speed boosting moves. In addition, Escavalier has a shallow movepool, forcing it to resort to Normal-type and low-powered moves to remain competitive. When one chooses Escavalier, one must be sure not to treat it as Scizor; Escavalier's main goal is to punch massive holes into your opponent's front line rather than sweep or scout.
While Choice Band Scizor has a more diverse movepool to choose from, one cannot deny the sheer power Escavalier has when equipped with a Choice Band; it has the ability to punch a massive hole in many things that don't resist Megahorn and even has the ability to 2HKO many Pokemon that do. For example, 252 HP / 0 Def Machamp is always 2HKOed by it and even 252 HP / 220 Def Bold Zapdos risks a 2HKO if it switches into Megahorn while Stealth Rock is in play. Pursuit assists Escavalier with countering Latios, effortlessly OHKOing it if it attempts to flee. Its usefulness extends to Gengar, Alakazam, Latias, and many more. The third slot is reserved for neutral coverage, with a non-STAB Return providing coverage on most Flying- and Fire-types. The fourth moveslot is Escavalier's attempt at inconveniencing Steel-type switch-ins. As sad as it is, Knock Off is likely Escavalier's best option against Skarmory, whereas Rock Smash can be used to deal up to 50% to offensive Heatran. Reversal is a slightly more maverick option, but it has the potential to become overwhelmingly powerful as Escavalier's HP decreases. Unfortunately, Escavalier's awful Speed makes it difficult for it to effectively use this attack.
Before putting Escavalier on your team, you need to consider if Scizor will do a better job. While Scizor has better Speed, Technician Bullet Punch, Superpower, and U-turn, Escavalier has an immensely powerful Megahorn and better bulk, especially on the special side. The latter of Escavalier's selling points becomes even more advantageous in this Dragon filled metagame, as it can put that precious Dragon-type resistance to better use. For example, 248 HP / 0 SpD Scizor is always 2HKOed by Latios's Choice Specs Draco Meteor after Stealth Rock. Escavalier, on the other hand, will always survive in the same scenario even if Latios rolls maximum damage on both turns. Other advantages include never being 2HKOed by Gengar's Focus Blast even after Stealth Rock, being able to guarantee survival against a Kingdra's rain-boosted Life Orb Surf after Stealth Rock, and even surviving Timid Magnezone's Hidden Power Fire over 92% of the time.Team Options & Additional Comments >>>
Iron Head deserves mention in that it can OHKO Terrakion, but otherwise is not recommended due to Steel's poor type coverage. Swords Dance is an option to skyrocket Escavalier's Attack, but that awful base 20 Speed makes it difficult for Escavalier to take advantage of that boost. However, under Trick Room, Escavalier will be able to break through almost anything. The last viable option is Double-Edge. While indeed more powerful than Return, the recoil compromises Escavalier's excellent bulk.
Checks and Counters
The best counter to Escavalier is Skarmory; even with Choice Band and Swarm, Escavalier can only hope for a 5HKO with Megahorn, which is nigh impossible given that Skarmory would simply Roost off the damage and can use the turns in between to set up layers of Spikes or wear it down with Brave Bird. Aside from that though, very little will appreciate taking Choice Band Megahorn to the stomach. Bulky Ghost-types such as Dusknoir and physically defensive Jellicent can come in on Megahorn, survive the hit, and outspeed Escavalier to inflict burn via Will-O-Wisp.
For more offensive choices, Heatran is the top choice due to its 4x resistance to Bug-typing and its Fire-type STAB to scare or roast Escavalier. Conkeldurr takes upwards of 48% damage from Megahorn, but if there are no entry hazards, it can Bulk Up and recover the damage via Drain Punch. Otherwise, prey on Escavalier's abysmal Speed and attack with a reasonably powerful Fire-type attack.
Escavalier's Dream World ability is Overcoat, which is practically useless. Because of its Steel typing, Escavalier is protected from sandstorm, meaning the only weather that does damage it is hail, which is rarely seen. Shell Armor's protection from critical hits or Swarm's boost to Bug-type attacks are both preferred over protection from one weather hazard.