roccobike

I've purchased a few used MTBs. IMHO, the one component you have to check out carefully is the shock. Replacing it can kill an otherwise good deal. I've been there on both sides of that problem. I really like Specialized and the Stumpy is a light bike, but if it has the original Manitou SX fork, you'd better be sure it's working perfectly because finding parts for that thing, especially seals, is very hard. Manitou does not support those forks. It's a shame, they're pretty nice for a lower end fork. Ihave two and both leak. The Trek has a Manitou Axle Elite, same fork I had on my Rockhopper and very similar to the fork that came originally on my FSR XC. I like the Axle, it performs well with good rebound control in it's price range, but it is heavy (around 5lbs). As long as you know that, you should be good. Some have critisized the Axle for being soft. I've never felt that way about mine including when I used to weigh in at 220lbs. I believe you can still get parts for that fork. I had a slightly older 4500 and a 4300 that I used on MUPS. They were nice bikes. If the 4500 had been a larger frame I probably would still have it. I can't comment on the Windsor one way or the other. I'd tend to go with DirtPedalerB's recommendation if it fits you well. But if you don't mind looking at a replacement fork down the road, the Stumpy may be the way to go.
One thing I like about used bikes and why I like to go with them. If you don't like it, you can usually flip it for close to what you paid for it. That won't be true with the Windsor.