The 1S and the HL both have strobe (which can be shut off). I'm not a big fan because I think it over-complicates what should be as simple as possible. I did use a strobe for a while, and I think that it could have a use down the line with proper switching/user interface. In our training, I don't force anyone to turn off the strobe function, but I make students aware that I know how to turn it off. I've never had a strobe make it through the training without being shut off. It's too easy to activate inadvertently, causing distraction to the shooter (and other shooters on the same team).
The 1S is still bright, probably plenty bright, but the HL has a better beam profile (TIR lens) with a wide bright beam, which is an advantage in seeing what needs to be identified while minimizing the need to point the handgun directly at the person/object.