It also depends on how much you want to spend. A used 2-stroke will be cheaper to buy than the equivalent used 4-stroke. Having said that, you can't make or import new 2-strokes any more so if you want a brand new engine, you'll struggle to find a 2-stroke.
4-strokes have it in terms of efficiency, environment, cleanliness, and they're much quieter.
btw Welcome to the board!
A RIB is for life, not just for Christmas.