Lots of experience in 7 Super Sports with 912S 100 hp. Rotax.
Most with the Rotax 100 hp. usually cruise easily in the 115-125 mph range with 5.7 gals. per hour fuel burn on average.
Take off on hot day in Phoenix (105 degrees or more) 1,000 feet plus per minute climb rate.
The radial engine while heavier does real good on take off. Climbs seemed as good as the Rotax 100 hp. but cruise suffered some from the large flat plate area the radial presents. Maybe 108 to 110 mph cruise can be expected.
The Lycoming o-233 performs very well while again heavier than the 912 S it seems to climb very good but shows just a bit slower cruise speeds but not by much. Getting the right prop is very important.
I only flew one 3300 Jabiru 120 hp. equipped Kitfox model 5 and I was not impressed with it's performance. It was no match in climb or cruise for the 100 hp. Rotax. It sounded really nice though, what ever that's worth. It had some overheating issues that had to be addressed too.
I have no Viking or UL Power experience yet.