I have the 50 ETEC and LOVE it! Runs like a champ--very little maintenance, runs at low speed all day, sips gas, lighter than the 4-stroke and on and on.
I have yet to talk to anyone that has had a problem with one. The only drawback that I have found (such as it is) is that you need to use really good oil in it. All in all it is not really a big deal since it doesn't burn that much gas (and I am pretty sure that not having to go through the 4 stroke maintenance counters the cost pretty quickly).