I like the gun and it shoots great. The GAP is reported (here and other forums) to have a "better" recoil than the ACP or 10mm. Keep in mind "better" is subjective. As for being the best gun in all three catagories you are losing sight radius which supposedly cuts down on your accuracy. But after you, your dad, and BIL win some GSSF guns you can get the "ideal" gun for all the catagories.
I see your logon has G35 in it. I recently shot a 37, 39, and 35 in the same course of fire including some 25 yard shots. I shot the 37 the best and the 39 just a little better than the 35. About the same amount of practice on the 39 and 35. Lots on the 37. So justbecause the gun is a subcompact doesn't mean it's not in the game.
I'll encourage you to get the 39 as it is a great gun. If you do I also encourage you to write to GSSF and nicely ask they add the MajorSub catagory back into their matches. This year they changed Major sub to Heavy metal. Major sub was limited to Subcompacts in 45 ACP, 45 GAP, and 10mm. While I like the Heavymetal catagory it kind of leaves the big caliber subcompacts at the mercy of the medium and larger frame big calibers. There is no catagory focused on the 29, 30, 39 any more. Hopefully if GSSF gets enough well written courtious request they will bring back the catagory while keeping the Heavymetal. The more the better. They kind of hinted they might do such a thing but being relatively few competetors with the 29,30,39 we all have to write in.