The best thing about 4-strokes is they'll swing a larger diameter prop than a 2-stroke. This isn't a benefit for all R/C airplanes but the scale ones really shine when they are 4-stroke powered. A good example is Great Planes' 1/5th scale RV-4. The real RV-4s are usually powered by a Lycoming O-320 that spins a 70" - 72" diameter prop. At 1/5th scale the RV-4 needs a 14" prop to be accurate. A .46 2-stroke just ain't gonna swing one of those!