I saw two of em break - In one case flying along level flight -- suddenly just slowed to a stop we pulled the top of cowl and case was split front to back - not hot - just split.
Th 3W guys promptly warrantied both engines and that fixed both -no further problems -this was 2 years ago as I recall.
There were problems- but 3W did fix em.
Friends of mine are professional pilots for RPV tests - I hear other comments also but this is a model forum not an industrial application forum