I tried the ALS... (after ten years of a more "conventional" retention holster). It was just too weird for me, and I couldn't find a decent exercise regime to build up my thumb strength enough to run a decent range day without feeling like I'd need a splint and ice pack on my thumb.
The CQC, on the other hand, while needing a little conscious effort to overcome the extreme bad feeling of using trigger finger to initiate draw, worked awesome for me after about an hour of practice.
Your mileage may vary.
Blade tech makes a decent holster, but I have yet to see a level 2 version in the flesh. They look a little hokey on the website photos.