I have been using a Safariland level II retention ALS holster on and off for a range holster and during dry fire for about the last four months. My criteria when looking for this holster is that it needed to fit my handgun with a red dot sight and flashlight on it and have a retention device that prevents it from being drawn until it is activated. I found the Safariland 7378RDS-7TS ALS holster on the the Safariland website. Their website is very easy to navigate, I applaud them for that. To find a holster on their website, you simply click the holster finder tab at the top of the website and then answer a series of questions to figure out which holsters they offer that will fit your gun setup.
The holster has worked very well for me so far. I ran into two small hiccups. Initially the retention device wasn't releasing the gun very smoothly. I had to hold the ALS lever back longer than I liked which made for an awkward grip on the gun during the draw. After about ten or twenty times of going in and out of the holster, the thumb release was working smoothly. I was then able have a good grip on my gun as I activated the thumb release and drew the gun. It looks like part of the plastic mechanism had to wear in on my slide and my guess is because it was not a factory slide. I am using an aftermarket Zev slide, so the dimensions are probably a little bit different. The holster did end wearing through some of the finish on the left side of the Zev slide on the rear cocking serrations. If you have a factory slide on your gun, you may not run into this issue. The thumb release wore in pretty quickly, so I don't really see that as an issue. Although, if you are worried about wearing through the finish on your slide and you have an aftermarket slide, this might not be the right holster for you. That is the only complaint I have so far, but honestly it is not on them to try to make this holster have good retention without scratching the gun with every aftermarket slide out there. That just doesn't seem like it would be possible to accomplish.
All in all I would recommend this if you are looking for a duty holster or holster for your battle belt. I have been very pleased with it and will continue to use it.
Have a safe and great weekend!