Jab engine reliabilty
No, the reliability of 3rd gen engines, and 2nd gen upgraded to 3rd gen specs, is very very good. These engines have accumulated a huge number of hours, enough to give very high statistical probabilities, and it is really looking better than Rotax.
There was a good article by Rick Frith and a second article by another author in the same online issue of RAA magazine, I think it was around May 2016 (dont hold me to that ) that sets it all out. Give that a read.