Don't buy just one, by a whole bunch.
I think they're great. I use them for everything. Track, wood, plastic. I even used one to cut some oak flooring (full size) when I needed a very precise cut in a tight space. I use a miterbox or jig when cutting to keep things square.
My problem is I bought only one. My LHS (not really, but the closest one) doesn't carry them. They carry the Xacto line. I broke down and bought one. What a piece of *&$#@ it is. I'd buy one online, but hate to pay $6.95 shipping and handling for a $3.95 saw.
Doc