I just ordered a Scubapro Classic Plus for PSD diving to replace my Scubapro S-Tek Harness with back inflation. I don't like the fact that it is harder to don over my dry suit, but for me jacket-style bcds are the way to go for PSD. Personally, I found I do not care for back inflation after having been initially convinced several years ago by other, more senior, public safety divers that I needed it. Here are my reasons for going away from back inflation (for reference: I've been using back inflation for PSD for the last 5 years...not a long time but long enough to figure out my preferences):
1) In a back inflation bcd, I found there is a strong tendency to be pitched forward towards a face down position when on the surface. To overcome this I either have to do a slight kick, lean way back to compensate, or not fully inflate the bcd. I also choose not to put non-ditchable weights on my tank or anywhere on my bcd that I cannot reach. Being pitched face down may make it difficult to survive if unconscious on the surface. I've found that jacket style bcds permit you to float very stable on the surface and face-out-of-the-water if unconscious. When on the surface, I want to be able to relax completely (this is important for multiple dives and/or a strenous operation) and I do not want to compensate at all by having to perform even a slight kick.
2) Because of the forward pitch, I found out while practicing rescue scenarios there was some difficulty doing rescue breathing particularly when the victim was not very bouyant. It required considerable effort to keep the person above water and fight the forward pitch, and I am a fairly strong swimmer and a strong person.
3) The Classic is a stabilizing jacket. I like the concept of the increased stabilization of the air being free to circulate around the diver...essentially: it is more stable because the diver actually "rotates" around the air in the bcd. I've noticed in PSD, I'm oftentimes trying to maintain a stable position in the water while being sideways, upside-down, on my back, etc., so this is welcome.
The Class has four D-rings, two high, two low. This is enough for me. I hang my pony on the right side and I've got two more to hang a float and a back-up light or whatever else I need readily available for the particular dive scenario. I like to keep all the other crap in the pockets! The Classic has four zippered pockets. Alot of the "extra necessary things" like my slate, extra rope, compass, and all the other stuff is stowed away and aren't entanglement hazards. I used to have hang all kinds of from all my D-rings and got tired of looking more like an accessory stand in a scuba shop than a streamlined and ready for action PS diver.
As far as comments about the Air 2. I love mine. I always use my pony too. This gives me multiple options when that panicked diver takes away your primary. Also when that panicked diver rips off your full face mask and realizes "oh, that's not going to be easy to put on so I'll snatch his pony reg!" It's just another, easy to locate option. I'll deal with the ascent issues once my breathing issue is solved!
I hope my view are helpful and certainly welcome any comments. Seems like most of the postings disagree with my points of view...