cerich:Salvo is a good reg, I was short a reg one day in cave country and picked one up(don't let my wife know, I had at least 40 more regs at home...) anyway, all of the current Oceanics regs have a lower work of breathing.
I'm not in anyway saying that oceanic makes a bad regulator. I own a DX4 myself (I have 92 hours on it with out a rebuild) and love it. I've also used CDX3's and CDX5's. IMHO the comparison on work of breathing is negotiable. I can't tell the difference in work of breathing between the regulators.