Hands on experience - it is an extremely nice running engine-easy starting and smooth running.
Comparison with ZDZ 60 -which weighs less - is that the 50 will not pull big props (24x10 MenzS) as well - All of this was done using tuned exhaust setups - we tried various ones -different lengths etc. and both engines were operated under " best conditions ".
if weight is not a factor- it becomes a simple brand choice -in 50 size comparisons
Against the new ZDZ50 - weight of the 3W is considerably more -and power - based on single examples only - pretty darn close!
No solid "side by side"data yet.
Best apparant comparison is that smoothness is about the same - the new ZDZ50 - is very smooth.