After all this palaver, I'm very bored of bikes but I have learned that I really, really like air-cooled BMW twins and that is all I now have left. I really wish the oilheads were as good as I like their size and ride too. But they aren't anywhere near as well made. I love the K1100LT too. Best fairing for a tall person that I've ever ridden behind. But they are water cooled and have foibles at this age. Boxers just don't have any real issues. At all. And their centre of gravity is so low they are a joy to ride.
Most bikes I bore of in a few months but I always come back to airheads and MZs. I think MZs are now too small and a bit annoying to ride though so perhaps no more of them. And one bit my ankle when I slowly turned the kickstart over whilst wearing slippers!
No great conclusion I can draw from my experience. Except perhaps that I wish I'd kept a lot of my bikes but I don't have a handy aircraft hanger!