I would have said to keep the Tohatsu. You allready had it, and admittedly there was nothing wrong with it, so i don't see any sense in getting rid of it?
Tohatsu seem to get a bit of a bad rap from people all over the world.
So what if they are a cheaper motor, they're meant to be. They are more simplified in design, cheaper to purchase, cheaper to service, and cheaper to replace parts, meaning overall they are far cheaper to run.
I've seen (and i'm sure others have) many a time where a more expensive make, be nothing but problems, and the cheaper alternative offer nothing but trouble free running, and also vice versa ofcourse. Which goes to say that there is no guarantee that one make vs another be any better, more reliable, or perform any differently.
Aside from regular maintenance, it's a bit of pot luck also. The fact that you allready had the Tohatsu, knew it's background, and had no major issues with it, i would have been more inclined to stick with it.