Originally Posted by Damien.
In Merc/Mariner I trust.
I may be biased because I am a Merc/Mariner dealer.
Really - I'd never have guessed!
I think there is very little to separate the quality of the Merc/Mariner, Yamaha, Suzuki, Honda, ETEC, Tohatsu (have I missed any?) brands in terms of quality of support/engines and its rare to hear horror stories which don't seem to be isolated incidents. They are all offering long warranties now. They all have a reasonable dealer network. Do you have anything constructive to add as why the Merc/Mariner is a better engine? If you happen to be a Yam or Suz dealer in the future would Merc/Mar still be better!
Depending on which companies have recognised service centres nearby might sway your decision for you. Hopefully you won't see much of them, but if you do they'll be pretty important. If you don't already know them then you might want to talk to them first and see if you like them. I know a dealer who prioritises repair work for customers who bought there engine with him rather than the cheapest place on the internet. I also know someone who drives 30 miles to get his engine serviced, passing a dealer only 5 miles away because he doesn't like/trust them.
Personally if any dealer used the arguments I quoted above - they'd be off my list! I'd expect a constructive response along the lines of "These are all good engines from large reputable companies, and you wouldn't go wrong with any of them. Although you might find that XXX is ligther/has more acceleration/uses less fuel (preferable with an explanation, e.g. because it has a different gearbox, more sophisticated engine management etc). OR "ours might burn a little bit more fuel at full throttle, or be a bit noisier - but its actually a much simpler engine which means that its simpler and cheaper to service, and less to go wrong". Even if its still exagerated sales BS (do you think that if we repainted the the engines so it was a blind trial that the average boat owner could tell the difference in performance between most of them) - at least its trying to differentiate.