I purchased a Quad 400 four years ago and the only "problem" I've had out of it is that the serving seems to wear pretty fast. Since I don't own a bow press I had to take it to an archery shop to have new strings and cables put on it every year.
Other than that it is IMO the best bang for your buck out there. It's accurate, pretty fast, and relatively quiet as far as Xbows go. I've killed plenty of deer with it and every one the arrow has been a pass through.
Even though i'll probably use my Matrix this Fall I plan on keeping my Barnett for a back up and use it when my wife is using the Matrix.
I think it's like anything, there's always a lemon in the bunch. I must be lucky because I got a peach, lol.
