I've switched to using my P7M8 for IDPA instead of my USP45. IDPA is set up so you compete with similiar guns.
1911's in 45 or 10mm are in Custom Defensive Pistol. 8 rounds only in the mags. USP45 can be shot in CDP.
Stock Service Pistol, basically any stock pistol, but first shot must be fired DA. 10 round max in the mags. P7 and USP can be shot in SSP.
Enhanced Service Pistol, 9mm or .40. DA/SA guns can be shot SA for first shot if it can be carried cocked and locked. Limited modifications allowed. 10 rounds also. Most SSP guns can be shot in ESP depending on caliber.
Then there's the revolvers.
The P7M8 has many advantages and disadvantages.
Quick follow up shot due to the light slide and fast action.
SA trigger, no 10 lbs DA.
Slide release is in the squeeze cocker
Single stack mags easier to grip for tactical reloads
8 round mag capacity. P7M13 would be a better choice. Or until CJS starts making the extended +2 baseplates for the M8. Basically two reloads to get through a 18 round stage vs. 1 for the guys with 10 rounds.
Hard to recover ejected casings for those that reload.
9mm is ideal for SSP and ESP because it meets the minimum power factor.
For IPSC, it is dominated by the 1911's though.