I've been by there and I agree, the owner is a nice guy. He mentioned that he is working on buying a dive boat which could be an excellent addition to our diving options. He has an interesting selection of gear, but not usually what I'm looking for.
I tend to find myself at Undersea Divers in Beverly for most of my purchases (probably bought 80% of my gear there). Bob Boyle (imho) treats divers well. He has always taken care of me and my wife (we bought our first wet suits from him in 2004 and our dry suits in 2006).
I have also bought gear from Andy's Sports Shop in Fitchburg, Cape Ann Divers in Gloucester, Burlington Scuba in Burlington, PG Dive in Newton, East Coast Divers in Brookline (I bought at the old Framingham location), and mass Diving in Natick. I like to spread it around to the good and decent shops so they survive and we have options.