You mention reliability in relation to Rotax. ULPower would have to sell 10,000 engines a year for 10 years to come close to the proven in-service hours Rotax has accumulated already.
Tell that to all the 912 flyers who are grounded right now waiting for the 6 month backlog of floats to clear up so they can fly again!

The old argument about Rotax's high rpm's being a concern has long since been proven a non-factor
It may be a "non-factor" but he said:
(those high RPMs really don't appeal to me)
As they don't appeal to many - like me - high revving, with another maintenance point, being gear driven. It's not an argument (unless you make it one), it's a preference - whats wrong with that?

Why would a manufacturer need to produce 100,000 engines to be deemed as reliable? Yes Rotax has sold a bunch, but not all 100% reliable - they've had a few issues to. To be "as reliable" does not necessarily need to equal quantity sold or "in service hours" - which by the way - is a complete unknown.

I like pepperoni on my pizza too!