BMW's aren't alone. "Way back when" my wife had a 1984 Nissan Sentra - They dealership wanted ~$700 for a new Hitachi carb. That was in 1993 or so.
So we sold the car and she drove our Mercedes 300SD.
On our more current activities-
My E38 is just near 100,000 miles. No issues to speak of.
My W126 has near 200,000 miles. Other than the 'minor' issue dealing with a chunked timing chain (and subsequent top end rebuild... he he) no real issues there either.
My 2001 Yukon - 110,000 miles. I have bad luck with the window motors for some reason. Two been replaced, one needs to be replaced and the other is still working (knock on wood). That and an electronics module that dealt with the transmission - That's all I've dealt with. Heck - I even have 3/8" of brake pads left on every corner.
5 years and those miles later.
You can and will find people who have had great luck with just about any car as well as those that have had terrible luck. I actually think the 'near old' BMW's are actually a pretty decent car to own and keep going. I'd maybe put the E39 in that category. The E38 is also pushing it. The E32, E36, E34 have simpler electronic systems that (I think) lend themselves to being dealt with on an easier basis. That and also have had more time to have hacks like us come up with 'home grown' fixes for things that othewise (if taken to the dealer) would be simply swapping one electronics box for another.
Just a thought. I've even had a friend that had a neighbor whose Toyota bought back as a Lemon....
Personally - I'd not hesitate to own a 7 series (or 5 series).
Hey - I do!!!!
Seriously - A good PPI and your own instincts will do more good for you than any advice here.
Good luck-