Let's see, which holsters do I have? I have a 10 year old blade tech for a G19, 2 Comp Tac holsters (G19, G34), and 2 Ky-tac holsters (G17, G34) and a FED Paddle from Galco (leather, thumbbreak). For competition, the Ky-tac is the fastest, then Comp-tac, then blade-tech and Galco. The Ky-tac has the least retention and the Blade-tech has the most (of the kydex holsters). The Comp-tac is in between, but you can loosen the retention screws that grab the trigger guard. The Blade-tech has the least amount of tension adjustment.
You can order a Ky-tac holster for IDPA or USPSA. IDPA is legal for USPSA, but the opposite is not necessarily true. The IDPA holster sits a little bit closer to the body. Some rule about "seeing light" through the belt loop. It is still very fast. The only drawback, I waited 4 months for the holster.
Comp-tac was delivered within a week. I ordered the locking paddle, as recommended by Matt Burkett. It's a little bulky, but still a great holster. Be aware that belt loops may interfere with adjustability.
I used a Blade-tech for many years. It has a good combination of speed and retention. If you are looking for speed, I'd probably choose another holster, but if you have to climb walls, crawl around, etc. I'd go with Blade-tech. I don't know how long the wait is because I got my holster directly from Tim Wegner, while shooting at Gunsite. He actually drove down with a car full of products. You can also order Blade-tech items from Brownell's.
Hope this helps somebody.