I never mention SQ improvements because DX220 alrd good SQ either in Mango OS or Mango Andro... even swapping AMP from AMp1Mk2 or AMp8... it is just matter of ur preferable Sound Sig.
using Lurker add on, to get UAPP and make the apps make sure to bypass Android Driver in Android mode, so u can exp like Mango OS (at least that's what I felt).
if I must choose one, I choose mango OS... I prefer the dynamic in low volume, since on Mango OS, I just need Volume 9 of 100, to get the dynamic. Again this is my preference... based on my current gear combo...
Now, I stick with UAPP until iBasso can update the nightmare search UI better in Mango OS