Kris, I have had a '94 K75RT with 63k miles for 6 months now and have put 8k miles on it. Total invested is under $4k including battery, rear tire, brake pads, complete fluid change, professional paint on some dinged fairing parts and some rubber bits.
I love this bike, and recently bought a '92 K100RS to keep it company. I don't know if it is a peg dragger, but heck, I'm 66 and not that much of a thrill seeker. She does respond well in the twistys, and the power is more than adequate to attract the attention of law enforcement even on the super slab. Even with the fairing and large windshield she will accelerate smoothly to at least 95mph in 5th which I think is pretty decent for a 750cc touring bike.
Service is fairly straightforward on routine maintenance items. The exception is the clutch splines which are about a one day job, and may be the reason your clutch has a hard pull. I have read the mechanical horror stories about these bikes, but to be honest, so far both of mine seem to be trouble free. I think they are like any other motor vehicle in that if you keep up with the maintenance schedule they will reliably get you home. Yes, parts may be expensive from the dealer, but a week or two of watching eBay will turn up almost any part you may need at a greatly reduced price, and there are lists of substitute maintenance items that are readily available at local auto parts emporiums.
One unusual thing about these bikes is that strangers feel comfortable coming up to me to say how nice it looks or tell me about their past Beemers. Never had that happen when I had my Honda, while at least a dozen people have approached me last summer alone. I dunno, but it seems like maybe the BMW badge lends some sort of respectability to the bike and some people are curious if it is actually made by the same company that makes the cars.
All in all, the classic K's are nice bikes and great deals for the money. I have been hooked and am now part of their cult following. I think your friend is a fool.
