I've had two mark VIII's in my life. I haven't had a big problem with either car. I had a 97 Lsc and a 94. My 94 i picked up for a 1000 and i literally have not had to replace anything besides brakes and tires.
I bought mine in pretty rough shape from a freind at work. Tranny bad, brakes pulled severly to right, a few interior quarks. But the price was right $1k. I put about $2k into it to make it right. It has been extremely reliable. Exceptionally comforable. Very safe with it's weight and dual airbags. Power is excellent. handling is great. All in all both my wife and I both fight over who's going to drive the Mark each day. It's 12 years old and we have 2 new cars to drive. We just love it! In fact, I recently bought a 93 so that we can each have our own. There are quarks in the Mark, but what car does not have quartks? I was never a Ford or Lincoln fan but now converted.
The Mark VIII is definitely not without flaws, however it is a really great car. It has never left me stranded, repairs and maintenance are very affordable and fuel mileage is reasonable for a RWD V-8 coupe. Update 7/4/16: I have ran into some needed repairs as of late, but that is to be expected on a 22 year old car. Still a great, reliable, comfortable car. Update 1/7/17: I have parted ways with the Lincoln because the repairs needed outweighed the use left in the vehicle. It served me well for 2 1/2 years. The reality of these cars is they are a luxury car and they are now old, as such things will start to break. If you are keeping one long term I recommend changing over to a coilover suspension as the air ride is very expensive to keep up. I also recommend the J mod for the transmission which will improve the life of the transmission as well as shift points. Also I recommend joining the Lincoln Vs. Cadillac forum and the Lincoln Mark VIII enthusiast community on facebook as they will provide much needed advice and point you towards parts which grow more and more scarce. I loved my Mark VIII and I continue to search for another.
This is my first Mark that I have purchased. I would suggest this car to anyone looking for performance, value, and sporty. There are some issues to contend with such as the terrible headlights that burn the reflective material inside the lights, and the cracking of the buttons on the climate control. The only other complaint is finding parts for this car. (Thanks eBay) Other than those issues, this car has been reliable, fun to drive, and depending on your driving habits can be quite fuel efficient. (I have seen 30 mpg on a long highway ride!) The air suspension makes this car ride like a foreign car, and the power is just incredible.
The car is an absolute pleasure to drive, The engine packs a large punch when you step on the accelerator. With its 280-290 hoursepower it accelarates faster than a new Mustang GT. Many people look at is as an old man's car but when you drive it it's anything but=)