I came within inches of buying one online. Spent who knows how much time on the phone with a fellow who I felt incredibly comfortable with but ended up not doing it
only becuase I found a guy in my office building that gave me as good if not better a deal. I would buy online only if you have educated yourself well enough to know what you are talking about and have confidence in it, otherwise I wouldn't do it.
What I would suggest is finding a wholesaler in your area and work with him/her. They'll treat you right and give you a much better deal than a retailer. Stay the hell out of the malls.