The A380 to me seems better built and higher spec.
But the Dingoo A320 only had a handfull or Emulators like CPS1/2, Neo Geo MVS, NES, SNES, SMD and GBA out of the box, the community worked hard to provide other Emulators both on Native OS and also Dingux which was a Lingux port again the community ported.
The A380 company just used the improved emulators the community worked hard on, without giving any credit to their hard work. The whole story has more to it than that, but pretty much the community that made the A320 what it is, will not (well a large number of the coders etc) support the A380 because of the way it has stolen and not given credit to others hard work.
I think the A380 has attracted some community to help improve but not at the level the A320 had.
So the A320 has more support but then its what A320 do you get nowadays when you order as there are many versions knocking about, also the A320 is not exactly a very well built system.
If i had a A380 i would be able to give a unbiased view, but with a few A320's i dont see them being that much more powerful in terms of a worthwhile upgrade for me.
If i had no A320's then it would be a tough as, but i guess the A320 has more support.
You could ask the A380 section for help and see what they think of them.
I got my Dingoos 2nd hand for about £45 each, myself i also think the Caanoo is worth considering.