I ride the Mobius, and they are comfortable. They seem to stay in place well. Once I start riding, I don’t really notice them. They take a while to put on, as you have to adjust the straps each time (no quick-clip option). I can’t really compare to other braces as I haven’t worn other ones. I started wearing the braces not only to protect my questionably creaky knees, but to protect them from the cheese-grater Alta shrouds, as they were shredding my inner knees. I think I have mostly learned to grip the bike farther back, but back then I was very annoyed with the shredder shrouds.
Also, I highly recommend some kind of knee brace sleeve or sock or pants. They come in alot of different styles, mostly thin lycra. I use the Thor knee brace sleeves that go from about mid calf to mid thigh. They provide a bit of friction-protection for your skin, wick up the sweat, and I have found they keep my leg cooler. They also seem to keep the knee braces from getting as stinky, since dead skin doesn’t get directly transferred to the brace from being in direct contact with your leg. I generally fold the top of the sleeve over the top of the brace, and they don’t slide down.