No idea on V-70's only that the first year or so of production there were electrical reliability issues. I have a 95 850 turbo and contrary to many of the posts here, I'm very sastified with the vehicle. Taking into consideration you have to perform the routine maintenence, it's a good ride.
Majors that were covered under warranty
1) A/C compressor
2) Heated seats ( these will always be an issue)
3) window motor

Things I did myself
1) Balljoints, struts, tie rod ends
2) Timing belt, water pump
3) O2 sensors

this does not inlcude brakes, etc.

No major surprises except the drivers door hinge and heated mirrors (cheap)

Have 175,000 miles and she still runs well, no smoke and minimal oil consumption. 8 years later, I still think I made a good choice.