I dived a lot with just a backplate and wing; after a while, I added padded shoulder straps which were nice on my 1mm suit; when Abyss liquidated his inventory, I bought two of his padded harnesses, and they are great. I also paid $34 each for them with a bunch of freebies thrown in as well.
If you go between singles and doubles a lot, the padded harnesses can be a little time consuming to rig, and doing it on a moving dive boat would not be fun.
Also, the backplate slides inside these things, and I had an unsecured 6-pound steel plate come sliding back out and right onto my right big toe. There were sailors down here who had to cover their ears over my language that day.
I like the comfort of the padding in the back, and it all just molds itself to you. I wouldn't spend too much on one of these though - the plain old plate itself is plenty comfortable, and with the slip-on shoulder pads, you avoid lots of wear-and-tear on your shoulders and divesuit.