I had one of the ALS ones and did not care for it. The SLS one that I had seen took up more room, or at least appeared to, than some of the others on the market. Ther eis also certainly an argument against commonality in retention systems when you start talking about potential weapon confusion. I believe that is part of why Blackhawk's Serpa Taser holster draws in a different stroke that the Serpa concealment and duty holsters.
I am not really a Blackhawk fan, but do like the Serpra Taser holsters.
"Logic is rarely the engine that propels a police department forward."
-David Simon in "Homicide"