There is little doubt that the DA will last longer.
Now that the DLs have been here for over a year, I am beginning to observe them come apart.
Three main issues -
bearings going bad, which is something you cannot do much about.
threads for the plug get jammed, which is something you should be careful with, but once messed up, requires a new head.
standoff supports breaking - if not mounted perfectly square, they can break over time - its cast, not machined.
I have seen 3 or 4 at our field developing issues and require a rebuild. Personally have not seen DAs developing the same issues and hope I don't get to see any of mine...
ORIGINAL: victorzamora
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.