Since the internals of the engines are all the same, there is no one best engine manufacturer, as there is only one! The accessories and PCM tuning are the only differences, and some of those are the same as well. Sustained high RPM and load will shorten engine life, it is simple physics. As you approach the upper limit the wear increases exponentially, so depending on your red-line or what is suggested in your owner's manual, operation less than 20% of red-line will go a long way giving you many years of trouble free use of your GM Marine engine, adapted by the various engine suppliers.
I forgot that Ford has added an engine to the marine industry, but the GM engines are everywhere.