I just can't resist even though I have little to add to T.O.M.s post.
See my signature line?
The 3W 28i was the engine that prompted me to use it initially. I tried many other lesser products before I asked a a "
Wise Old Man" for his suggestion on a decent product. Cost was not an issue, reliability and performance were everything. (he has also since pointed me in the direction of a couple of other top of the range products that reinforced my sig line).
The reason you see very little posted about these engines is
1- As T.O.M. mentioned They cost a bit more to purchase than most wish to pay - it is a good investment though.
2 - As also mentioned previously, provided you don't kiss the ground with them, they simply work well and go on working well.
3 - Those converts who do get it and fly them are too busy enjoying their flying to be chasing info on line
I have a couple of them now, I have a 20/6 on one (a slow light scratch built fun flyer) and an 18/10 Biela on another that is regularly flown on a small Extra. I tend to run in new ones on an 18/8 for most purposes.
PM me if you are looking for easy ways to set the engine up in the plane, I will send you some photos of how I fit them.