islandgambol-
I have a 2005 Yamaha 90 (the first year Yamaha switched over from carburetors to EFI on the 90 4-s), and it's flawless. Still runs like a new car. Turn the key and go, even after setting for months. It's so well made, I wish Yamaha made cars. They do make musical instruments, though, and this motor sings like one.
I also have a Yamaha scooter, and it is much the same. I hold Yamaha on the highest step in the motor technology world, even above Honda and Suzuki, etc.
The Evinrude e-tech is an interesting motor. 2-stroke, EFI, oil injected, and more. The original skinny was that the e-tech 90 was actually about a 107 or so HP motor, which would be nice when you needed the extra push. The 2-stroke motor is said by Bombadier to have more low-end torque, too. When they first came out, there were some problems with them, involving overheating and oil consumption, if I remember right, but I'll let those that dealt with such issues, like Tom Brady, deal with them. They may have been solved by now. The oil required is a special type, since it's going to be burned in the combustion chamber, and its cost needs to be considered vs. oil changes in a 4-stroke.
If it were me, I'd choose the Yamaha kicker, too, partially so I could go to the same dealer for both motors, but also because the Yamaha 8 hp High Thrust motor has been touted very highly as a kicker/trolling motor by its owners.
Definitely get a High-Thrust kicker, as they push relatively large boats much better than those with smaller props, higher gear ratios, and fewer design-specific features.
Nope, I'm not a Yamaha dealer, nor a stockholder, just a avery satisfied Yamaha owner.
Good Luck, whatever you choose!
Joe. :teeth :thup