EDIT: dog beat me to it, but.....
Just a heads up; Tohatsu makes Tohatsu, Nissan, and Mercury (small Merc, under 10 HP) outboards. The only difference is the sticker. You can save yourself a couple hundred by getting a Tohatsu 3.5.
I bought a 3.5 from these guys:
Tohatsu Outboard Motor 3.5hp 4-Stroke
I'm happy with the outboard after a full seasons use. I use it on a 9 foot Achilles with HP inflatable floor. I have to use a tiller extension and drive from well forward in the boat to get it on plane. You probably won't get on plane with either choice. I got mine from Onlineoutboards.com for $850 no tax.
I am in no way affiliated with OnlineOutboards.com other than being a satisfied customer.