I've bought from them 3 times. The first two times were flawless, fast shipping and everything was exactly as ordered. The third time, not so much:
I bought a Zeagle Stiletto from them about a week before a trip. They price matched Scubatoys and shipped it quickly via two day air. Upon arrival, I noticed that the BC was loose and somewhat askew in the box.
It was new but on further inspection was missing a bungie cord that threaded down the left side. It seemed to be one that held the wing retracted. As I wasn't familiar enough with what else might have been missing, I decided to return it and re-order on my return. So I called them, asked for and received an RMA and sent it back with the understanding (it's stated on their website) that I'd be credited within about a month.
After about 6 weeks that never happened so I called them again. While on the phone with the sales rep that had taken my order, he said that he was crediting my card immediately and apologized for the delay. That also never happened as a month later there was still no credit.
So I filed a dispute with my credit card company who investigated and issued me a credit - DiversDirect did not dispute my version of what happened.
If you're ever laying over in Miami/Ft. Lauderdale they have a great store just off I-95 by the FLL airport.
Personally, now I just buy from Scubatoys...