If someone has to convince you of the "why" of buying the BMW, then don't do it. Either its in your heart or its not.
I was at a local dealer today and someone had just traded in a late model FJR1300 Yamaha. It was blue, just like my K12GT. I sat on it just to see what it was like. I have heard so many Yamaha fans talk about how the FJR was such a great bike and all.
As I sat on it something just wasn't right, then it dawned on me. We don't really need motorcycles, they are an emotional thing. I thought of the few things on my K12GT that might need a little improving and they seems so petty. I thought of the things that the FJR might do a little better than my K12GT and they seemed unimportant.
My BMW has soul and I feel connected to it. Its an emotional thing, just like those Harley guys talk about. I guess you just have to look past the price and decide what your heart wants. If it is a bike with the best set of "numbers" then go with the Jap bike. But if your heart connects with the BMW forget the price as there is no logic that can ever justify spending that much money on a motorcycle like that. Either you love and want it or you don't.
I would never try to talk anyone into buying any kind of motorcycle. I can tell you what I like about different ones or I can quote numbers, but passion has no logic. Too me my K12GT was a dream I had for a long time. Before I died I wanted to own a new one, one all my own. Other bikes were nice but they were just not "the one". I love its looks, it feel, its sound. I know the people who designed and built it had passion too, I see their handiwork in it.
If someone has to talk you into it, go buy an FJR and enjoy it, they are a great bike. A local dealer has a good deal on a used one that looks good.