As someone who has used both electric and gas, I say it all depends on where you use it. If you go out offshore and you have wind and waves, you should have your sails up. If it is not too windy, the electric can push the boat as long as you don't have current. Problem, no taking your boat out too far on calm days and if you are far out there and the wind dies, you have to wait it out. Also a downside I find is that your range is very limited with electric power. So you won't want to run it full all the time, in fact never run it full unless you absolutely need to. It will drain your battery very quick on full! So power it up just enough to keep control and get you moving. You never know when you will need to run it full so no reason to crank it up when not needed and drain your battery. Another downside about those electrics is when it comes time to drop your sails and go in, you could have a problem if the winds are high. Not to mention docking and departing with strong winds.
Positives about the electrics... nearly zero maintenance, very cheap, quiet and uses no gas. More positive is super lightweight so you can take it on or off the boat with only one hand. Oh and another thing they are extremely reliable. All you need is a good battery with enough charge and motor comes on.
Indeed, gas outboards are powerful but maintenance is expensive and frustrating at times. For example, my Nissan 9.8 is in the shop and has been in the shop for nearly 4 weeks now. First they tell me $75 an hour, take about hour and a half to do a annual service. Then they call me and say $365 to replace the water pump, engine is overheating. Next call, they say $765 because there is some corrosion in the lower unit which needs to be all cleaned out. Welcome to outboard motor ownship I suppose. I have to get it serviced because I want it running great and in top shape.
I think the Torqeedo that someone mentioned here is the way to go but those are just very expensive. Those are an actual electric outboard, not a trolling motor and they are pretty powerful.