Re: IDPA/USPSA Which one? Or Both?
I'm not going to say "don't but a Serpa" but I will say that you should Google Serpa ban and continue your research and try to be more informed about your holster purchases.
I will say that you could not give me one to wear, especially if I were a novice shooter looking so start in the gun games.
Blackhawk can make a good holster, is look at thier CQC holster which lacks the button. Most I've seen in competition that are usinng a Serpa have disabled the locking mechanism.