I've owned three Honda outboards over the years and they've all been excellent and trouble free. Never owned a Yamaha, but haven't heard any complaints from those I know who use them.
Personally, I'd go for the lighter of the two as either will probably get you to 5 knots easily and you state you didn't need the charging advantage.
Charlie P. P31-2 #80 CATNAP
To travel hopefully is a better thing than to arrive - R.L. Stevenson
I suspect that, if you should go to the end of the world, you would find somebody there going farther . . . - H.D. Thoreau