If I could verify maintenance records for it and it were in good shape, I'd have no fears. Try and locate the previous owner or the vehicles service history via the VIN. Frequent oil changes are a must. I think the 850/V70 cars are extremely well built and will hold up as long as long as any 240 with the proper care. Unfortunately, there's less work a DIY'er can perform so expect to visit the dealer more often. Keep in mind that ANY used car might need a major $ repair - tranny, engine, etc. The 850's are known for AC evap cores and rear seals being expensive to replace.

I've bought and driven several high mileage cars well over 200K. My experience has been good and very cost effective with Volvo RWD's. I've recently begun my first AWD experience and hope it's similar. Having good mechanic skills helps a lot with costs.