I have had a couple of the SLS; I hated them because of my small hands. The hood simply was too hard to rotate reliably. I have a couple SLS; one was actually the level 3 SLS/ALS combo until I took off the hood. I have found them to be good for what they are. They are not concealment holsters and I don't have a light mounted. I knew that there was a problem with the Glocks and the lights years ago, but have not kept current on that as it doesn't matter much to me now. In addition, if someone is even trying to mess with your holster enough to crank off a round that way, you need to pay more attention and break their hand or fingers when they try.
I am not a fan of open carry, for many reasons, but if I did have some circumstance in which it was sound, I would almost certainly be using one of my old duty rigs. Under no condition would I use/own/allow the Serpa; the index finger release is only one of the well documented problems with it, and there are a lot of agencies and trainers that prohibit them, for well established reasons. While TTAG might be right in his critique of the holster in question, it is actually not designed for what he is doing; Safariland is serious about doing a lot of presentation training reps before using these holsters, and support for the Serpa is what we lawyers call impeachment evidence.