As a percentage of Busas on the road, the number with tranny problems is negligible. The Busa tranny, or I should say Suzuki sport bike trannys in general, shift like butter.
I had one, I know lots of guys with Busas, no tranny problems reported. No more than any other brand for sure. If you are getting rid of your Busa just because you think the tranny will go bad, you shouldn't. If you or a prior owner has abused it, that is another story.
You know how shit goes on the internet, one guy has a problem, others think they have it, people get carried away, and all of a sudden a rumor turns into perceived reality because of hysteria by the masses.