It's amazing how much people can debate these low end boxes. :)
I found them both to be fairly equal, the Edision has a few extra bells and whistles that'll cost you around 30 quid more but the Zgemma looks a bit better on the eye and has a better remote.
If you want Wifi and Bluetooth then pay extra and grab the Edision, if you don't need it then buy the Zgemma, it's cheaper and prettier.