Thanks for all the advice guys. One question about the simple setup (i.e. non-padded): Isn't it uncomfortable when diving in thin protection suits? I've often dived in just a rash guard or a 3 mm tank top style wet suit top. I'd be worried that the unpadded webbing would gnaw at my tender armpits, especially on dive trips where we do 3-4 dives a day.
I spent most of 2009 doing 4 dives per day, every day, in either a 3mm or rash vest. No issues at all with using metal backplate and/or simple harness. The crotch strap didn't cause a problem over boardie shorts either.
Bear in mind, that once submerged, the harness is not bearing any weight. It is a weightless environment.
The added benefit is that the wing is
directly supporting a lot of your required weight (backplate, trim weights)... so you really won't feel like you are being 'hung' from the harness.
Also, the harness is fitted very loose. Over-tight harness is a common mistake for new BP&W users. They want to cinch it tightly because that is what you
haveto do with a jacket BCD
(otherwise it'd flop around). On a BP&W the waist belt and crotch strap keep the kit secure... the shoulder straps are really loose. I can literally take my arms out of the shoulder straps whilst still strapped into the BP&W at the waist...it is THAT loose.
If you did experience any chafing in the armpits or shoulders, then just get (cheap) neoprene tubes to pad the harness. I doubt you'd actually find that you needed these... but they'd still be a whole lot cheaper than a 'deluxe' harness system.
Most of the 'deluxe' harnesses sold by BP&W manufacturers are to novice BP&W divers who feel (without trial) that they must 'need' the fancy harness. It's nothing more than a 'comfort blanket' from their previous experience diving with a poodle jacket. Very, very, very few divers would actually need a more complicated harness...and when they do, it is normally to serve a specialised need.
I'd hazard a guess that 80%+ of comfort/deluxe harnesses end up at the bottom of a wardrobe...or being sold on Ebay...