I have a 1997 740i and have had no major problems. You have to regular oil change maintenance and car. Have a good mechanic, I use Bimmersport and don't take it to just anyone to save a dime. There are a lot of ex lease vehicles so check the maintenance package and service records. My suggestion spend the little extra and buy from BMW Dealership i.e BK Motors in Waterloo. They are out of town, excellent service and down to earth.
There is a BMW 2000 blue sports series at Erin Mills autocenter right next to Mr Transmission in excellent condition and I feel sure you can get an excellent deal
Best of luck