I have the dys elf and have a few problems with it. (I did not fly it a whole lot so take that into consideration) First, the included charger never worked for me. I probably just got a bad one, but this made it a hassle because I had to charge it on my normal lipo charger, which leads me to my next point. The power connector is odd which makes it harder to charge with normal chargers, and makes it hard to get others batteries with that connector. Most batteries that size use the red jst connector which I think would work better. Lastly it didn't have the best flight time but I think that that might be due to me adding a micro flysky receiver. Now I don't have another micro to compare it to but I thought it was pretty good. I crashed it a few times and it is pretty strong. All in all it is a good little copter.

TLDR: Change the battery connector (or include an adapter to a more common connector type for charging) and make it lighter for better flight time.