Depends, what size? How much do you want to spend and what kind of customer seervice do you want? Just make sure it is an American Vendor, for the after sale service. There are more gas engine companies than there are glow. But keep in mind that htey don't make a gas engine for the average .40 or .60 size plane. When you get up into the 1.20 size planes is when you can make the switch. Take a look in the Gas Engine Forum here on RCU.