Model_Aviator,

Boy, that's a tough one. You'll get a lot of opinions and most will be based on personal preference including mine I guess. It all depends on how big you go, how you want to fly, and if the price of glow fuel matters? Gas engines are really coming on in the market as far as power and weight compared to glow. Some gas engines are about the same weight as big 4 stroke. For example, the new line of DLE engines. They are light weight and produce a lot of power for their size. Big glow engines produce a lot of power but like you said, only up to a certain size plane. The YS 1.40 and 1.70 is a popular power plant for big Pattern planes so compare those engines to what size plane you want to fly and what gas engine you want to run. For 3D, glow will propably be better suited but that's just my opinion. The choices for what combo you want to run are almost unlimited and it will take a lot of research and trail and error to find what you really want. To find that perfect combo takes a little doing.