I'm on my third E-Tec 90 at present and couldn't be happier (but at 320lbs doubt you'll ever see one on a microskiff....). Yes, I'm in hard commercial service and lucky enough to be on BRP's guide program (and on OMC's before that....). Since I've never had anything other than a Johnrude since 1973 I may be a bit biased.... Although I'm on their guide program I don't get any freebies, stand in line for my maintenance like everyone else, etc.
Now for the nuts and bolts... don't buy an E-Tec unless you're confident of a strong authorized BRP outfit within reasonable distance to you. Most early failures I'm familiar with are almost directly attributable to improper initial setup by the dealer... You don't want just any marine mechanic working on one (the lower unit maybe, since they're no different than they were years ago...) the upper end is designed to be worked on by a factory trained tech, with the correct software for that year/model and all work will be done with it hooked up to the computer.... These motors come set up to run XD 50 oil (semi-synthetic, in a pinch you can substitute any TCW3 oil....). Your tech can set the motor up to run XD 100 oil - but in that setting you must run XD100 oil and nothing else, period. I've never run any of mine on anything other than XD50 since I can easily find it in bulk re-fills.
Yes, the 300 hour service interval is the real deal... No, you don't have any break-in period with these motors. They'll automatically double oil for the first 10 operating hours and they advise to vary your rpms durinng that same first ten hours.
Yes, you can run wide open from the start but remember to vary those rpms.... I'll range from 3500 to 5500 with my motors (about five minutes each then up or down 500 at a time or however I feel like doing it....). Yes, these motors are actually cleaner burning than any current production four stroke anywhere... Yes, the fuel consumption rate is very good. In my case I ran 115 Johnson or Evinrudes for years before going to just E-tec... With the 115 motors the best I ever did was four miles per gallon (even the fuel injected V4... and that was being very careful to run no more than 4500 rms. Bolted on the first E-Tec 90, ran it anyway I pleased and got five miles per gallon... a full 25% improvement in fuel consumption (and a 25% boost in my practical operating range.... very important if you're running 65 to 75 miles a day in the 'Glades the way I normally do.... By the way all the fuel comparisons were run on the same beat up old Maverick skiff....
One last item. Unlike other brands E-Tecs aren't particularly fuel sensitive at all (as long as your fuel is clean and not loaded with water). I've never used anything other than standard alcohol laced gasoline ever....