I've been mostly happy with saltwaterfish.com, but honestly I don't order much from them these days almost entirely due to something that's not really in their control - they ship via FedEx, and I don't trust FedEx around me. There are a lot of factors that go into your choice of shipper, and I'm not going to criticize them for using FedEx instead of UPS. But locally, FedEx just doesn't treat packages well. On my last order from saltwaterfish, I had them ship to the FedEx facility rather than putting it on a delivery truck - the facility is only 10 miles or so from me, so I figured I could minimize stress on the fish and get them in sooner if I had them held at the facility and picked them up myself.
When I got the fish, they showed clear signs of rough treatment from FedEx. I had three or four fish, and none of them made it a week. Two of them were dead within a day.
Again, I want to stress that I don't think that was on swf. The fish were packaged and labeled well (something I've always appreciated from them), and they honored their arrive-alive guarantee where it was applicable. But if FedEx isn't reliable around you, that is something to be aware of.
Their selection is great and pricing is great to fair, so if FedEx shipping is reliable around you I don't think you'd be disappointed with them. Also, I know "fish" is kind of what the name implies, but I've picked up a few corals from them as well and found them very nice, especially for the price.