That does look really cool. Is there any realistic chance of it being ported to the Zero? I only looked very quickly, but I don't think it's open source, and they seem mainly interested (understandably) in getting it on major platforms like XBL and Android.
If you port it, I guess... but that would be a big job. Why bother? It will be running Dingux out of the box.
The main competition I guess would be Chinese Android devices like the Yinlips and JXD's. They are very different types of devices, and for all sorts of reasons I don't feel like going into, not as good as the Zero for emulation.
The Dingoo is much older, weaker hardware. The Zero is far, far better.
As for the NeoGeo-X, definitely not worth it. The NG-X is using a similar SOC as the Zero, but is otherwise way underspec'd, and has still not been fully cracked. Plus it has all sorts of hardware/software problems, design issues and shortcomings. Check
the forums at neo-geo.com for details; a lot of people are returning them for refunds. If you're interested in emulation and indie software, I would definitely NOT choose a NeoGeo-X. Heck, even if you're just interested in handheld gaming in general, I would not choose a NG-X. There's a reason why
NG-X production has already ended.
I did a lot of research before jumping on the GCW bandwagon. For what it does, it is simply the best thing out there these days. But that is providing what it does is what you want.