JD Power quite accurately describes the 850 as generally mechanically reliable, with lackluster reliability for features and accessories. Since 1999, when I got my "pristine" 1994 850 with only 31k miles, I have replaced/repaired the following:

1. 2 front pwr seat cables for reclining seatback
2. upper motor bushing (lower motor mount still needs replacing)
3. odometer remanufactured
4. PNP switch
5. shiftlock switch
6. rear washer repaired 2x; currently nonfunctional
7. radiator

What still needs doing:

1. heated mirrors don't heat, but move ok
2. ABS controller is toast
3. mysterious, but significant A/C problem (getting it checked out on Tuesday)
4. upper plastic dashboard piece rattles like crazy after ODO repair; seemingly in chorus, wagon's in-floor cargo door also rattles like crazy
5. passenger power seat switch for reclining seatback doesn't function continuously; rather, the passenger has to "pulse" the switch
6. rattle in right front door speaker since before I got the car

Re the ABS controller, the units don't fail *completely* for a relatively long time; mine has been getting slowly worse for over a year. In order to see if this particular ABS controller is on its way to car part heaven, try doing some hard braking. The car generally diagnoses the error a few seconds after you release the brake pedal at the end of a solid stop; then, the controller goes offline until the car is restarted. Of course, this isn't 100% fullproof; sometimes I can drive for 2 hours without any sign of trouble. This is about a $600 repair.

Good luck!