Hi Greg,
I've become quite farmiliar with these cars and would definitely recommend them as being quite reliable. Working at a Volvo dealer, I mostly hear the bad stories and not the good ones, so I know what can go wrong with them. I would recommend the 1998 model over the 99-00 models because they are a little easier to work on and diagnose problems (cheaper repairs). This is because in '99, Volvo made a few changes to the cars including a drive by wire throttle system(no throttle cable that links the gas pedal to the engine) and a distributorless ignition system. These two systems in particular had a few bugs in them for the first few years (99-00). Still good cars, but I would recommend the 1998 S70, but get the computer scanned by a Volvo dealer before you buy it to make sure that there are no error codes, they won't necessarily appear with the check engine light. In particular, the ABS control module can have a problem that lights up the ABS light on the dash then turns off. This is an expensive part that can cost upwards of $800. Don't want to scare you away, just make sure you're informed. Hope this helps out, if you need any more info. e-mail me at greg_neilson@canada.com
Greg Neilson
Barrie, Ontario
Canada