To me the only difference is in the landing. Or it if goes dead stick ( on a glow or gas plane) Twice the wings is twice the drag. You are not going to glide around with a bipe if the engine quits. You need to be finding a place to land now. That being said I've never flown a foamy bipe. But as someone said above, if you can handle a single wing you can handle a bipe.

David