I've got one. I generally like it. I don't like the boltsnap that it comes with so I took it out and use it with a normal double ender. Unlike some people I like locking my reel any time I have to do any sort of manipulation with it. With a screw-lock reel you end up faffing about with it so you don't usually lock it off until you tie in somewhere. I've never dropped a reel, but I've seen other people drop theirs. It's just less of an issue if it's locked off. The slide lock allows you to lock and unlock quickly and easily, potentially adding another preventative layer to "inadvertent line deployment." I also find it easier to achieve proper line tension for tie-offs.
I like it for rebreather diving because I still have a hand free to do things like correct buoyancy, clip a chicken, etc. while dealing with a reel while tying in. It's not a huge deal, I've never had an issue using a regular sidewinder reel, but it's easier for sure.
The only thing I don't like that I can't easily correct is the spool itself. I'm a fan of delrin, the plastic that Dive Rite uses for the spool portion can brittle with age and form cracks. I've never had this problem with any of my delrin reels/spools. One of the reasons I quit using other Dive Rite reels is because of their propensity to brittle and crack. We'll see if this ends up the same.
It's also a little sloppy with lock-up. With a normal screw-lock reel, it's essentially infinitely adjustable. The spool locks exactly where you want it. Because the slide-lock engages in the slots on the spool, there's play. Only a couple degrees, and it's a minor annoyance, but I'd prefer finer adjustment. I'm picking up a lathe pretty soon and may turn a delrin spool with finer "locking slots" in it to see how I like it.