I have the 2800mA S2+ and it gets hot on high very fast. If you’re biking in cooler weather, it should be ok. I never run mine on high while biking long distances though because of run time and I live in a very warm climate most of the year. There are some interesting mods that people have used to add extra heat sinking for bike likes though. I’ve seen a heat sink from a CPU modded to go around a flashlight.
M1 with an OP reflector is rather nice. It doesn’t light up as wide an area as an S2+ at similar output levels, in my experience. It tends to be a fair compromise, as was mentioned, between the throw of a C8, and the flood of an S2. I like to use mine as a good all-around, multi-purpose light. It’s tough, not too big, good heatsinking. But I EDC an S2 at 2.1A max, the form factor is just better for me for every-day tasks.
If I have to loan out a general purpose light, its one of my M1’s. With a 3B tint, it’s perfect. I have one in a 4C tint that very much feels like an old style incan light, but with much higher output of course.
I sometimes (ok, often) feel bad that I can’t use all of my lights all of the time.
I started out with one of those on my handlebars. It is just OK and I got tired of having to readjust the holder on the bars. If you have a 1” diameter light, the universal U shaped piece of rubber (without the 360º functionality) is the best. I’ve been using mine for four years and have hundreds of hours holding C8s of various generations without any problems.