id buy the tank from them.
buy your skimmer, lights, powerheads and pumps online.
they have good prices on live rock most of the time, so id buy live rock from them.
if you buy fish from them, i would quarantine them.
there corals are usually nice and healthy and at a good price too.
and there sales people are there to make a sale, so ask here before buying anything expenisive. theyll try and talk you into buying a lot of stuff that isnt always neccessary.