Simply put the best car you can buy for a few grand. Build quality/ride/handling/braking rivals new cars. Steering is ok, loads up well, good feedback but poor on center and is not as quick as modern cars. V8 with a 6spd manual (proper) gear box is a dream. These things take a good deal of maintenance and repair, simple as that (find me a 16+ year old car that doesnt'!). Parts are reasonable, labor is pricey. Parts availability and technical info is outstanding (old bimmers have a great group of owners!) I like this car a lot but it just isn't the best fit for my needs. I would prefer to sacrifice some of the greatness of an old BMW for a less hassle newer car.
The new cars are sufficiently updated. Know what you're getting into, it's going to need maintenance and repair - $1-3k per year if you are handy with a wrench. Cost is fair, but takes too much of my time.