I'd recommend looking through this forum for various comments. A common theme: the electronic throttle body on the pre-03's are prone to failure and require replacement in the range of $800 - $1000. That hasn't been my experience -- I'm passing on what I've read. Otherwise, the S60 seems very reliable mechanically. I've had no problems with my 03 non-turbo, for what that's worth. (Sure, the check engine light that goes on after each fill-up is getting annoying, but the performance has been great.)
Good luck with your decision!