Had the car for two years now and runs brilliant! Interior looks untouched, manual sunroof never leaks, only bother is air conditioning stopped working a while ago. Needs freon I bet.
When you buy an older Volkswagen, you must keep on the maintenence. I was lucky and found a lesser driven car. So it's original engineering for German driving can still be experienced. Seats are Benz-like without leather.
Being a notchback, the car has some body lean, but grips and handles like a true german engineered car. My previous car was a '93 Benz 190 series and my Jetta handled just as well, but the ride was a bit more bumpy than a Benz.
Only note: No airbags and an annoying seatbelt arrangement. The airbags on my Mercedes made me walk away from a head-on collision to Silverado. They're essential.
Also the 89 Jetta can only start when your seatbelt is plugged into the shoulder strap on the door. You can't start the car without the seatbelt fastened. And it makes it hard to enter and exit the car.