@drrich2 has given some good advice and I'm especially in agreement with this statement above. One thing to consider with regulators is servicing. They'll need to be serviced periodically. One thing you don't want to do is buy a used reg set (nothing wrong with that) only to find out that your local dive shop doesn't service that brand. You have a few options. You can buy a reg from your local shop, then you know they can service it. All the big name bands (e.g. ScubaPro, Aqualung, Atomic) make their servicing proprietary. That is, they don't allow (train) individuals to service them and they only sell the service kits to authorized dealers. And the cost of the service kits to the consumer is ridiculous.
Hog and Deep6 do it differently. They'll train individuals to service regs and sell you the kits. Deep6 signature regs even come with a kit for the first service. If you don't want to learn how to do your own service, you can always just send your regs to them. I've used ScubaPro and Atomic regs. They're nice regs, but I've recently moved to Deep6. Aside from the bonus of service that I mentioned, they're great breathers and cheaper than the others.
One nice things about a BP/W is it's modularity. For diving with your 7mm suit, you can throw on a 6lb steel backplate, and that's 6lbs off your weightbelt. Want to travel? You can save 4lbs and use an aluminum backplate.
Enjoy the journey!
