There has been quite a bit of progress with the JXD S7800, I think fixed kernels have been released (by the community, not JXD) so you might wanna check what performance is like now as it will be different to what you hear on the rumour mill.
I don't know if you can play GCW on a TV yet, you will have to check on here for updates. I don't think analog out, HDMI out and USB OTG are working yet though.
JXD are no longer making consoles now btw, I suppose the same is true of GCW and company support was never great with either. You are probably better off checking out other brands and seeing what is due for upcoming release.