The 92A1 has a recoil buffer in the frame - but it's really to increase frame longevity. In actual firing of 9mm ammo, you won't feel any difference.
It really boils down to whether or not you want a rail.
I have prev owned two M9A1s and two 92A1s in the past. I prefer the standard 92FS - it balances better, IMO, without the rail. At the moment, I have two 92FS models and a 92FS Brigadier. I like the guns iwth no rail... Although, I will admit that I have an oder in for that new Wilson Beretta Tactical 92. I've been looking at pics for months now, and everytime someone posts up one that they bought, it has been tempting me. I can no longer resist