For IDPA:
Auto - XD, Glock or M&P in 9mm.
Revolver - S&W K or L Frame would be hard pressed to beat, though a 4" GP100 would be no slouch.
For USPSA:
Auto - XD, Glock or M&P in 9mm.
Revolver - S&W 625s dominate period! For revolver division you are limited to firing 6 shots before reloading. If you bring your 627 and fire a 7th round without reloading you get kicked to Open division. The only place a 627 makes sense is in Production division and you are still disadvantaged 2 rounds to the autos.
I said 9mm for the autos because it's cheaper to shoot, gives no scoring disadvantage in Production and it's also a great round for steel challenge which is a great way to get your feet wet shooting comps and a hell of a lot of fun.
Auto - XD, Glock or M&P in 9mm.
Revolver - S&W K or L Frame would be hard pressed to beat, though a 4" GP100 would be no slouch.
For USPSA:
Auto - XD, Glock or M&P in 9mm.
Revolver - S&W 625s dominate period! For revolver division you are limited to firing 6 shots before reloading. If you bring your 627 and fire a 7th round without reloading you get kicked to Open division. The only place a 627 makes sense is in Production division and you are still disadvantaged 2 rounds to the autos.
I said 9mm for the autos because it's cheaper to shoot, gives no scoring disadvantage in Production and it's also a great round for steel challenge which is a great way to get your feet wet shooting comps and a hell of a lot of fun.