Dude, bikes all depend on the actual quality of what you are looking at. The bike may be a good deal, or it may be a really bad deal. I mean, good wheels can run upwards of 200 bucks by themselves.
All these people telling you it is a 'good bike' without knowing all the components really aren't telling you much.
S&M makes some regularly good frame and fork sets, but how much are you paying? Which year is the frame and fork? What components come with the bike? What condition is everything in? How hard was it ridden before? Did he buy it complete? What 'custom' parts have been added? Etc., etc.
It is like asking if a Haro is good. Some are a lot better than others and components make up about 75% the cost of a custom bike setup. So just asking about S&M without any additional details isn't the way to get good info.