One guy that flies at our field every now and again has one DA50 and like 3 or 4 DL50's. He swears by his DL's. It's been debated ALL throughout RCU which engine is worth the price...but it's really simple. They're both great engines. The DA will last longer, and is an American company (one of the few left), and is a true group of innovators. My money would go to DA, just because they're the originals...but that's besides the point.

Any 3D airframe advertised by any reputable company as a 50cc will 3D very well with a 50cc engine. The DA50 has better power-to-weight than many others, so it may do better than others. From what I've heard, Aeroworks planes are awesome with their respective DA engines...like they were built for them. Like nitrowing said, they pull in excess of 30lbs...also depending on the prop.