The 850 estate appears physically large due to the slab-sided styling. The rear boot drop-off however aids reversing as you can see exactly where the rear of the car is. A few days into driving the 850 and you will be squeezing through gaps that smaller cars baulk at!
Performance depends on which one of the many engine variations you get... I got the 2.5l 10v petrol which is a good torquey workhorse without high insurance costs. Acceleration is good, with lots of torque right up to motorway speeds and beyond. The ride is comfortable, stable, and safe.
Fuel consumption varies from 30mpg (UK) on a motorway run, to 23mpg around town on short runs.
The quality of the vehicle means further costs for me are limited just to servicing.
There have been problems for the range though. The ABS sensor ECU may fail, the air con evaporators seem to be of variable longevity, and brake rotors may warp. If you get a good one, you get an excellent car, so check the history thoroughly.
Now replaced by the V70 with softer styling, the 850 can be had for bargain prices.