True, I look at the glow to gas transition as an engine progession from smaller to larger planes. There's very little overlap for me. I'd say on the 120 size aircraft you can use the big bore glows like the Saito 220, YS 160DZ, Moki 2.10 etc. Or you can use a gas engine on the same planes. Then you can do a comparison. But as mentioned, once you are 80 inch and above it's all gas for me. As far as a "throw it your trunk and go" plane, it's a small glow engine (or an electric foamy).

I have electric, glow, and gas engines for all different sized aircraft. I'm not always in the mood for dealing with a big plane when I go fly.