I just shot my first idpa a few months back.. I used my everyday setup a Glock 19 under a tshirt, I got alot of compliments from alot of seasoned shooters because I pulled my shirt up and drew from a king tuk iwb holster, my theory is if your going to run a idpa event and wear one of those "shooting vests" you better wear your "vest" all the time. I didnt like how I saw all these people thowing this flimsy vest out of the way all while im thinking to myself, thats not what you wear all day every day. I guess my point is if your going to do idpa for nothing but the sport whatever, but it is a great way to enhance your performance under stress and tell you if your every day carry gear is up to snuff or if you can even manage it, I saw a guy, a very nice respectable man in his 40's out there using a blackhawk holster and he couldnt manage to activate the index finger release, I talked to him afterwards and said hey man i know your bummed out but you just found something out now that cost you a few seconds on your score , not out on the street where it really counts.
Just some food for thought
Cheers, Dave