Might as well through my 2 cents in.
I will never buy a 2-stroke again. I am a 4 stroke fanatic. Say what you want, but I have know switched 4 boats from 2-strokes to 4-strokes, 250hp, 115hp, 75hp, and a 25hp. I more than double my fuel milage, I can tell little difference in performance, no more buying or worrying about mixing oil (which is going sky high), and they are super quiet. Yes they are heavier, more on the lines of your boat, I switched a 25 2-stroke to a 25 4-stroke on my 1448 Alweld.
Comparison with 2- 240lb guys, 8 gallons of gas, TM w/battery, diamond plate floor, and 120 qt ice chest w/20+lbs ice.
-----------------Yamaha 25hp 2-stroke 90lbs ?+/- --------Yamaha 25hp 4-stroke 170lbs +/-
top speed GPS----29MPH----------------------------------29/30MPH
fuel consumption--50+/- miles 6gals ------------------------90+ miles on under 6 gallons
Comparison empty
2-stroke 34MPH and 4-stroke 32MPH
The biggest performance difference I see is loaded and empty MPH on the 4rs. The 4rs seem to me like a diesel truck, They run the same empty or loaded. The 2's have a little higher top end.
E-tecs- I work for a marine defenece contractor who makes a wide range of commercial boats. If they are outboard powered, they have used Yamaha since they started until 07'. In 07' evinrude made a deal with them and they installed e-tecs for about 6 months when the first one started having trouble. Now every boat that went out in that time frame has already had to be repowered (switched to Yamaha).
I live on the Gulf Coast where a large percentage of the people make their living on the water putting hundreds or hours a year on them. In some spots the boats out number the cars. If you ride around here, I challenge you to find one e-tec out of every 150 outboards on a commercial boats. I have owned Evinrudes in the past and I think that they made great motors 20 years ago. Don't forget that this is just my opinion based on first hand experience. You can ask 1000 people their opinion and get a 1000 different answers. Simply said, I don't trust them or Evinrudes warranty.
I also have twin - 225hp 2 - stroke Mercs. They came on a boat that we bought and I've yet to have a problem with them.
I am a die-hard Yamaha fan. I spent over 500 hours on the water last year and I don't trust anything else.
Like I said, this is my opinion.