Both are good engines - it is the support, policies and pricing that are the differences. Yanmar is there to support the dealers, not the owners. You must go thru the dealer for everything if the warranty is to be valid.
When I had a mis-Installed exhaust
and it sucked saltwater on a new engine
(and the dealer left it sit for 3 days). Yanmar defended the dealer! Had to take the legal route
, and ended up with a beta ... dead simple and easier to work
on yourself. Cheaper parts
and easier availability (tractor dealers everywhere if marine
are not available).