I've spent quite a bit of money over the years at Service Photo, which should give you some indication of the type of place it is. I wouldn't go back if their prices were lousy and the staff was unfriendly. It is easy to order online, but Service Photo keeps me coming back.
I have found their prices competitive with online retailers like BH Photo and Adorama. I recall that I have had them price match with those two retailers on more than one occasion. And remember, there is something about being able to inspect the gear you are buying before you shell out the money for it, even if it is new. For example, you can bring your own camera in and test a lens on it before you buy.
In my experience, I have not found their in-stock items to be lacking. Just about any lens I've asked about, they have had in stock, including longer and rarer super telephotos. In fact, I can only think of one instance, a Zeiss lens, that they did not have in stock... not exactly a typical lens, but regardless they still have Zeiss glass in stock (just not the lens I was interested in).
I've bought used gear from them and I've sold used gear to them. You never quite know what you will find in the used section, but I've gotten some real gems from them at competitive used prices. Again, much nicer to buy from them, be able to inspect the gear, and have a return policy rather than some no-name eBay seller who wants top retail dollar but won't back it up with service or a return policy. I actually found a camera for a friend of mine in California. I e-mailed him pics, the price was great, and he made arrangements with them to have it shipped to him. How can you beat that!?!
They have a very nice selection of film, both in 35mm and 120 format - B&W, color negative, and slide. They also have some 4x5 sheet film. With film use dwindling these days, it is nice to have a local place where you can go and find a nice selection of film in-stock, rather than ordering online. Also, plenty of film developing gear, including a nice selection of different chemicals.
The staff there has always been courteous, willing to help, and knowledgeable, not just about new gear, but also about older and vintage gear, different types of film and developers, and various accessories, such as lighting, filters, tripods, etc.
So, overall, I'd say if you are thinking of buying online, head to Service Photo first. They know their stuff and they'll treat you right!