I'll give you a summary of both pokemon
Pros: 145 base speed, making it the fastest pokemon in the Unova dex, and a good 100 base Spatk, making bug buzz cause some damage, and a okay movepool.
Cons: 40 base def and 60 base spdef make it very frail, allowing most pokemon to OHKO with a neutral move.
Pros: High 135 base atk, workable 105 base for both defenses, one weakness.
Cons: Slow, no gyro ball, no coverage for weakness, only one steel atk type move(Iron Head, Lv37).
I say that accelgor is perfect if you want a sweeper, and escavalier is for a T-Room team