I have a Pro QD and have been pleased with it.
Positives:
- Easy to use weight pockets (velcro)
- Both ditchable (up to 10 lbs each) and non-ditchable (5 lbs each against your back) weight pockets
- Easily-adjustable pivoting shoulder straps that make it more comfortable
- 6 D rings (shoulder, chest, hip)
- 3 air dumps (1 on back right hip, one on right shoulder - I never use this one, one at base on power inflator)
- Built in clip in the right pocket -- good for hooking your car keys on (if shore diving) or other tools (shears, etc.)
- Durable construction -- I've used mine for about 40 dives and it still looks unused
Negatives:
- Pockets, while large, shrink substantially if you use the ditchable weight pockets. That being said, I can still fit a pair of shears in my right pocket and my rolled up Halcyon dive alert marker/safety sausage in my left pocket.
As I said above, I've been happy with it. You might also want to pick up the latest print issue of Rodale's ScubaDiving magazine. They review a bunch of BCs, including the Sea-Quest Pro QD and the Pro Unlimited.
Hope this helps
-LD