Electric!

It's hard to idle a gas motor slow enough unless you have a trolling plate, drag buckets, or a drift sock. Plus a lot of idiling isn't good for a gas motor... more hours and maintenance. There's also the fact that you will be breathing a lot of carbon monoxide and if you have a 2 stroke, the oil that goes with it... not to mention the noise, electric motors are much quieter.

I'm not saying you can't do it with a gas engine, but for me an electric is much better.