My rule of thumb has been any plane requiring a bigger glow four stroke engine then the 1.20 then I would go to gas. Today nice gas engines like the DLE and CRRC are cheaper then a glow engine and you also save on the required field equipment needed to operate glow engines. There are now some smaller gas engines on the market and the cost is down on them too. I haven't used any so I can't report on them at all. Go to the gas engine forum to read what users have to say about them. Gas engines are simpler to operate then glow engines and require almost no servicing at all and aren't effected buy weather conditions, no needle twisting required once you have them in tune. It's a pilots choice but today if someone is just starting out in the hobby buying gas or electric isn't a bad idea. I have several gas engines but I have a bunch of glows so they get used more often in my planes. Go read up on the gas engines you are thinking about. There is no better, they both have there following, gas is easier and cheaper.