If you're getting a gun specifically for IDPA, a full-size gun that allows you to get a lot of your hands on it will be your best bet. Also, I would avoid DAO or LEM guns. You want a DA/SA trigger or a Single action only if you're going 1911.
Personally I prefer a heavier metal-framed platform. The more recoil my pistol can soak-up, the faster and more accurate follow-up shots can be, also the more stable the weight of the weapon as you empty your magazine. If your pistol starts at say 2 pound fully loaded and when you're empty it looses 25% of it's weight, this will play into how much you have to adjust to handle the weapon both in recoil control and just holding it.
For this reason, I shoot a Sig P226 e2 with the SRT trigger setup. Being a "stock service pistol" it also doubles as a nightstand gun in the house.
On the other hand, I also have been known to shoot my HK-P30 which is my daily carry gun. It's the opposite of the advice I just gave, but I helps me to maintain a decent level of confidence with either platform.