I bought an 850R last June as found my M3 coupe too small for a second baby !
My wife uses it most of the time & she likes it, its so easy to drive being auto. iv'e not had any problems with it yet, just had 130k service which was £229, personally i would say that parts for it are probably as expensive as a BMW if not more, Mine runs as sweet as a nut at 130k, its quite a hard ride on uneven road surface due to 205/45/17 as standard. My insurance is quite cheap though (group 17) £286 f/c. Like the other guy said they are quite juicy,get anywhere from 230 to 320 miles to a tank,about 25 mpg or 28 on longer journeys. I'm well pleased with mine as its performance is quite good & they are so practical,brilliant if youv'e got kids & lug stuff about. Also got lots of toys, mine has, self leveling rear suspension,heated seats,3 position memory seats,cruise,aircon,tracs,elec roof,centre arm rest converts into kids booster seat, boot changer as standard & loads more.
I would deffo recommend one but try & get one with full volvo history, turbo's normally fail from 140k onwards.

the other good thing is you never see them about much,R model is quite rare.

Pic of mine.