Operating my Rotax-powered VLA as a VH machine, I suspect that I have still taken a (hopefully small) hit in reliability relative to traditional aero engines in the other aircraft I fly, but it's a corner of the operational space that might yield some interesting stats, assuming there are more than a handful of aircraft included in the Rotax/VH category.
I have probably tens of thousands of hours of Rotax time with my signature on it. (maintenance) I will take the Rotax over the American air cooled engines any day and twice on Sunday