Here's what I know from first hand experience, I've spend a lot of time on e-tec powered boats, I can first give you a run down of known problems I've seen, this is the FIL's boat I'm referring to, the 2009 90 we had had one coil and one injector go bad, it had around 180 hours when the coil went down, injector a little later, it also had the lower unit let go but I firmly believe it got water in it and then froze over the winter, there was zero oil in it when I went to see what was wrong, sold it with 300 hours
Neighbours 2008 60 has had one injector go bad since new.
The 2011 150 he has now has around 225 hours on it and so far just a low oil sensor has failed, it was showing no oil when there actually was oil.
2008 175 on 1850 BR that the PO of my boat has has had zero issues, it pulls hard and I got 63 gps out of it the one time he tossed me the keys and told me to take it for a spin, I never fooled with the JP as I didn't want to push my luck with his boat.
Some positives with the e-tec is winterizing, it fogs itself and your done, if you want to use it again no big deal, just do it again next time you shut it off, it's quiet and throttle response is great, another plus is you can start and run a e-tec with a dead battery or even no battery, I myself started the 150 with a rope just to see if I could do it, and about 3 years ago we were on the other side of the lake 7 miles from home and the battery in my checkmate was completely dead, we took the battery from the 90 and put it in my boat so I could run home and the 90 ran home with no battery at all! Ran perfect. Which my Merc will not.
The fuel and oil consumption is very good, all this said I've spent very little time around new Merc stuff so I don't know what they are like, there are two 2100's on my lake with 300 Etecs that look like they run good, faster than anything I've got lol, but I've never been on them.
My dealer is the Mercury racing dealer for Saskatchewan, his slogan is or was I should say "call the Merc man" and now he sells almost all etec, so they must be doing something right.
I understand where your coming from with them always doing test with the 4 strokes and not opti's, I would like to see that to.
Like everything I think it comes down to preference, some guys like one some the other.
Here's another vid showing a etec on a pontoon and not a real boat
The father in laws 23ft aqua patio, it runs 47 GPS with a 150 etec
http://youtu.be/8liZliasLjg