I rode a Tass for a while. The thing with Fishers is that they used what they called Genesis geometry, which I think was mostly a longer top tube than other bikes that same size, and IMO made the bike feel a little bigger. The thing with mountain bikes is that the sizing is less of a science and more of an art than road bike sizing. The best way to know what fits is to test ride it and see how it feels. The Tass was a solid bike, but that bike is old enough that I don't think I'd pay much more than $150ish for it, and that's assuming everything is in good condition.