I bought the car at 120,000 miles. The first thing to go wrong was the fuel pump failed. I took it (towed) to a shop and the tank was so rusty that it had to be replaced as well. No big deal, however, poor design led to rust.
Aside from that, the engine and transmission have been almost bulletproof save for the small mechanical things failing, i.e: Air pump, alternator, water pump, starter, wiper motor.
Due to the XR7 suspension package, the car handles better than some front-drive imports. I'm very satisfied with the ride and after owning a 1986 Cougar GS, there is a world of difference between the two; as far as suspension/drivetrain is concerned.
Mine wasn't optioned with the power moonroof, so I had a pop-up sunroof installed which made the interior a LOT better to be in.
The sport buckets are great for long road trips and the fingertip speed control is more than adequate.
I agree, the 1988 mercury cougar xr7 is one of the best cars I've owned. The engine in mine hit about 180k before basic maintenance was needed. e.g. alternator and starter.