I have the Ocean Reef Neptune, and I like it, although it is VERY sensitive to intermediate pressures of the first stage(s) you attach it to. (Flutters when out of adjustment or the chin strap’s not fitted properly) It’s tricky to tune, but is comfortable to wear in cold water. For warm water - I prefer the ease of breathing a standard regulator.
I can’t comment on the OTS, as I haven’t worn one long enough to really familiarize with it.