There are more differences than I can comment on in a short quote. Gas is Easier to set up a plane and get going, and easier to get a fast plane. I find park flyers easier to learn to fly by yourself. If you want an electric plance to perform and look like a gas one, you will need quite a bit of learning as most normal kits do not seem to include performance power setups, they are designed more for the park flyer setup, where as with a gas plane, just get a kit, slap on any motor(mor or less) and you are good to go.
Keep in mind, gas is dirty and noisy. If you want more ask, and tell us your likes