2wheelsforme - The K1600 sure is a nice bike. I've sat on one, but not ridden it. I agree with your concern about reliability. BMWs are not Hondas, that is for sure. I've got an R1200GSA and it's a great bike and makes a great complement to the F6b, but the forum for that bike is much more lively with the stories of "X happened, now how do I fix it?"

jm21ddd15 - On the K1600, it looks like the valve checks are called for at 18k miles, BUT unlike the R1200RT (all R bikes) and the F6b, it's not a boxer engine with the heads pointed out, so the valves are a bit more of a challenge to get to. A quick search seems to indicate about $1k for that service, including spark plugs. Of course, on the F6b, THAT job is easy, while the air filter is a half-day affair.

That said, I've always been a proponent of riding what makes you want to ride more...I say take one for a ride and see if you fall in love.