I dailyed a '95 N/A 850 GLT for about 9 years, until about 4 years ago when it became a back-up/spare car, and last year we finally replaced it with an '05 Grand Marquis. We still have it, it's just literally been put out to pasture at my parent's farm.
The 850 only ever stranded me at my house twice, both times were the result of a bad fuel pressure regulator. I blame ethanol, and the second time I had replaced the original regulator with a used one from my parts stash, so who knows how many miles were on it when I put it on my car.
I did the usual repairs that you'll read about, PCV system is a bear but not insurmountable for the average DIYer/shade tree mechanic. The heater core is a bear, but more so if you're not flexible and have larger hands. I usually caution that if the A/C doesn't blow cold, I wouldn't even consider buying because the evaporator replacement is an enormous job, and unless you can hear the compressor grinding, chances are the evaporator is what's leaking.
I lowered mine on some Eibachs and Koni STRTs, put a strut tower brace and some sportier all season tires on it, and it was a fun-ish DD.
I put north of 250K miles on mine, hard to say for sure, as the odometer quit working at 146K.
I did replace the engine in it, but that was totally my fault. Thermostat failed, I limped it home, in work traffic, with the heater on, instead of pulling over and stopping. I warped the head. I found a complete long block, with fewer miles, for significantly less money than a remanufactured head, so I just replaced the whole engine.
In the end, it didn't leak a drop of fluids anywhere, but she was tired, and consuming oil a little quicker than I was checking. Only once or twice did I pull the dip stick out and not see anything. The old girl never complained and kept going.
I have delusions of doing something with her some day, maybe an homage to the BTCC 850s Challenge car someday.
I know I'm rambling. I like the cars, seats are phenomenal, and mechanically they're pretty robust. Just don't over heat them, and remember to change the timing belt, Whiteblocks are interference engines.