Zidoo has 5G WiFi so I think it's better because of that.
But if you have Ethernet all over your house then I don't see HiMedia as the best option.
If HiMeda releases H8 with 5Ghz WiFi it would be ideal
Dual-band wifi won't make any difference for most people. In fact, I'd argue that H8 external wifi antenna gives H8 an advantage in terms of wi-fi bandwidth. Zidoo X6 has no external antenna and relies on the tiny little wire you see on this photo:

Himedia hardware is better quality and Himedia are an established company well regarded for the support they give for their products. They have 6+ years experience building media boxes.
There are many unknown Chinese manufacturers selling hardware with specs better in some regards than Himedia, but most of it is junk. Not saying Zidoo is junk, but they certainly haven't proven themselves and the X6 hardware has fundamental design problems. In my opinion!
But.. I'm not getting into another Zidoo vs. Himedia debate. Especially in the Q5/Q10 thread. This thread is the place to go if you want to continue this discussion: http://www.futeko.com/newforum/index.php?topic=325.msg2217#msg2217