I can think of two personal incidents that highlight the differences between dealing with Yamaha and dealing with BMW. Both of these go back up to the manufacturer, BUT the face I had to deal with was the dealership (who, in the eyes of the public, IS the face of the manufacturer).
I've always been a high-mileage rider because when I started riding, my bikes became my primary means of transportation. My cars ended up sitting for long stretches of time waiting for bad weather or the need to haul more than one person or a lot of cargo. My bikes were never "toys" (which they are for the majority of Americans, at least) so I tended to put a LOT of miles on whatever I rode. A perfect example would be my 1999 K1200LT with 198,000 miles and my 2001 Subaru Outback with barely 90,000.
Anyway, back in 1988 I'd had my K100 for almost three years. It already had over 50,000 miles on the odometer. I was taking an "Owner's Maintenance School" up in Vermont and we were testing the battery (remember those days? You used a hydrometer to test the specific gravity of the battery acid to determine the state of the battery) and we discovered the battery was below standard. This was the original battery and the bike was less than three years old (back then, BMW's warranty was three years, UNLIMITED miles). The dealership hosting the school called BMW of North America and just like that, I had a brand new battery installed! I certainly wasn't expecting that.
Moving ahead a few years and my 1992 Yamaha Venture Royale. I had purchased it in 1993 as a leftover. After a couple of months, one of the helmet locks broke so since it was still under warranty I brought it back to the dealer. The initial response was: "Yamaha doesn't warranty any after-market add ons." I was incredulous! Those weren't after-market, they were STOCK and on the bike when I took delivery. Furthermore, they were keyed to the ignition so where the hell did they get the idea they were "after market?" It took awhile but EVENTUALLY they replaced the lock (but the new lock required a new key).
More recently, my old TMAX had an issue where the left side glove box latch broke so it wouldn't stay closed. Again, this was in the first year of ownership. The verdict from the dealer? Yamaha doesn't warranty the plastic trim pieces. TRIM PIECES?? This wasn't a trim piece, it was the ****ING LATCH!! That one was never resolved to my satisfaction and I ended up having to buy a new piece. That, combined with the lousy service I'd gotten from two different dealerships was the reason I traded in the TMAX for the C650GT. The Yamaha MAY have a better reputation for reliability, but if the dealer and manufacturer are going to treat me like that I'd rather go for the less reliable vehicle with better customer support.