IMO, gas is the best if you can get the power:weight:wingloading in a good ratio. 4c generally have better spool up wich is why so many people like them for 3d. Some 2-strokes are ported for big props and low rpm and produce 4c like spool ups.

On my 160 cap 232 i went with a DL 50cc and am so happy with it. I would concider it over the zenoeh g38. The DL cost 390$ shipped, weighs 50oz with muffler/ignition, and produces about 27-30 pounds of thrust. The spool up of the engine is just great for hovering. My GP Cap weighs 13.5 pounds dry and is hovering at about 25% throttle on the stick. Best of all, i can easily get a 20 minutes of flying on the stock 22oz tank. Big glows suck fuel fast. 22 ounces will last you about 10-15 minutes depending on the engine and you are burning gas that costs 13$ a gallon.