Ive got an '02 XC70 and it is a slight problem child BUT they changed the engine and transmission in '03 to a more reliable unit (am I right boys?), but even still mine has never actually stopped completely its just little gremlins that annoy me. Other than that though the XC is great, I love it, its great for IKEA runs (as demonstrated here:)
Brought half a kitchen home and still had room haha! Love it!
I don't think 250000 is bad, I looked at an 03 ex fleet one with 360 on it and still seemed to run fine, I didn't drive it though nor buy it, but there are plenty of 5 cylinder Volvos going around with tonnes of miles so they can't be too bad.
We are looking around for another XC for mum and her limit is 200000 kilometres but only cos she wants to keep it until she can't drive anymore and even though she does very little kilometres per year it'll add up in the next 20 years haha.