I have a friend with a k75 with 375,000 miles on it. I've got a k75 (93) and a k100(86) and love them both. I'll never own another brand of bike. The have great power, can get on either right now and not worry about riding cross country. Great in the mountains, lots of fun.
While dependable, any parts are a little costly. Also both of mine have had problems with the rear master cylinder leaking (maybe just. Ecause they are older), and the odometers seem prone to going out.
Like I said, not perfect, but for the money you can get an older one for its well worth the money