Well I am personally biased to MVVS engines. If you are on a limited budget, then it can't hurt to use it for now till you get the money for a bigger engine. You will at least have the chance to get used to the plane and then really have a blast when you get a better engine.

The guys advising you to go for 50cc gas know what they are talking about, it will really let you get the most fun out of the plane, low fuel cost, and clean (no gook to clean off)