Steve hit most of the good points. If the engine has a weak point it's the ignition but those are said to have been improved. The 3 point mounting system bothers some people but in thousands of engines I have not seen that to be a problem. Anyone that so desired could make a 3 to a 4 point mount if they wanted to, but being "different" has nothing to do with adequate mounting security.

About a true (on dyno) 2 HP, or 1,600 watts or so. Intended for a max RPM of about 8,000 using an 18" prop, keeping the engine within its best torque to RPM curves. Propped correctly they'll fly a 40+ pound plane for 24 hours at a time and come back for more over and over. Two sizes of cylinders and pistons, labelled "A" and "B" on the back of the cylinder and the top of the piston. The 28i has been a continuous evolution of improvements over the years. They started out a little shakey with some machine tolerances but those were all but eliminated a couple years ago.

They've gotten away from the "legged" wrist pin circlips to eliminate any of them breaking off and seizing a cylinder. That was very rare but was the most likely point of failure if and when an engine went bad. About 1 in 3,000 (numbers from experience) engines might experience a bearing failure where the bearing seal gets ingested by the bearing. They use very good bearings. If that ever happens it's always an "outer" bearing and easy to fix. Never seen a wrist pin bearing fail in one. 600-800 hours of easy life cycle before needing to change the ring. The piston and cylinder will still be fine at that time if you keep oil in the fuel and didn't run it hot all the time. Haven't gone beyond 1,000 hours myself so for this discussion I'll limit the ring life to 800 hours. Typically they are within about .003" of max wear at that point. Handles heat extremely well and will run up to about 180C-190C without too much wear. Performs best when run between 130C and 160C.

Pricey, but you definately get what you pay for. Hard engines to break and reliability is off the scale to the good side.