It's a pretty good bike. If looking at a hardtail I would think that you could find a lot more bike for the money, especially at the typical price point of a Trek, somewhere else. You'll need to budget money for wheel truing and a new wheel set at some point. Though I rode 28H wheels for over a year with no issues when I first started riding but I stuck to the more cross country type stuff and was pretty careful.
It's a great bike but you have to take into account what it's designed to do. The Superfly is a XC racing bike. You are paying a premium to get a bike with lighter parts. Is that something you are going to be able to take advantage of at 350 pounds?
You are probably better off spending less to get the X-Caliber which is also a XC racing bike with heavier parts. Alternatively you might want to look at the Stache which is a much burlier hardtail.