I am not one of those that Jim refers to but here is my $0.02 from personal experience with them
Some time ago, I asked one of the people Jim is referring to as to what is the best choice of engine in the size range. I was pointed to the 3W 28i. I purchased one to try it.

I now have many hours run time on that engine (well in excess of 200 hours) and it has not once missed a beat. I have since purchased 2 more of them and they also have in excess of 100 hours on each one and neither of those has missed a beat either.
One has been crashed twice and survived with no damage.

When properly tuned and propped, These are the most powerful engine in the 26cc to 32cc size range that I have experienced (and I have tried quite a few engines in that size range). Power curves are exceptionally good right through the range.
They can be a little fiddly to tune but if small adjustments are made at a time it is not too bad.

The genuine 3W ignitions can be a problem (I have yet to have one fail on me but I am sure I have just asked for trouble by saying that). However when it happens, an RCExcel ignition (and Hall sensor) will bolt straight on and work fine.

They have a 3 standoff mount that takes some people a little time to get their head around but it is plenty strong enough.
The long carb / intake setup can also be a little daunting to some as it is slightly offset but take time with the install and the effort is well rewarded, it really is no more work than any other rear carb to install. The other annoyance to some is the 6 bolt prop hub.

Overall quality is extremely good. The only minus for some people is the initial purchase price.

It is the 3W 28 that initially triggered my signature line. That thought got reinforced with some other offerings later on.