Depends a bit on what you use your boat for. Do you do much trolling? If so, you will love the four stroke. The first time you go trolling with no smoke or exhaust fumes, you will wonder why you didn't do it earlier. I've got a 40 Honda on my little barra punt, and while I have not been 100% happy with the motor, I do like the smoother idleing and fume free trolling aspect. If you don't idle around much, the simplicity of the two stroke might be the way to go.
Dave.