Re: Blackhawk Serpa holster for Glock?
Except for my IWB concealed carry holsters, all I now use is the Blackhawk Serpa. I've had people (training partners) yank upward on the pistol enough to start picking me up off the ground (I'm 6' 1" and 230lbs) and the holsters have never broken or released the weapon. Sideways pulls have only served to test how strong my belt and pants are.
The main complaint I hear is that some people try yanking up on the pistol before the button is pushed, therefore making it virtually impossible to release the weapon. But, IMO this is a training issue and is actually a good thing, as it means if someone else is pulling on my weapon and I'm pulling away, they'll never be able to release the retention device.
As for using the trigger finger to release the pistol, it's never been an issue for me. If your finger is on the button and simply slides up with the pistol, the finger will lay along the frame above and in front of the trigger just as it should. IMO, the finger going straight to the trigger is just an untrained shooter issue, and their finger would go there no matter what holster they draw from.
FWIW, I own standard Serpa holsters for G17(G22, etc), G21, 1911 and XD. For SRT use, I have the drop-leg level 2 for my 1911 (the level 3 wasn't available at that time) and the level 3 drop-leg for my G17.
The level 3 Serpa is by far my favorite level 3 holster, as it is both secure and very fast to use.