Wally, I know you're a sceptic and I'm no evangelist, but I give 'quiet thanks' for my Rotax 912 S2. After years of flying the Lycs and Continentals, I admit that it took me a while to believe that the little donk was a good thing. I've seen the religious debate in other threads and have nothing much to add, except perhaps that the Rotax has done well when compared in reliability and maintenance cost terms with my other engines. My personal philosophy is to take the operation and maintenance seriously and, even if I had a choice, I'd never have my engine maintained by other than a LAME - and one I trusted. If anything, I'm even pickier with the 912 maintainers. A less agricultural touch is definitely the go!
I hate to rely on anecdotes (for the reasons mentioned in my previous advocacy of maintaining a proper RAA database) but the best information I could get when looking at alternatives is that the Rotax does do better than the smaller Jab engine in reliability terms.