Just got my self an Xbox One the other Week and also got myself on the dashboard preview program with One Guide working for the UK.
Hooked it up to my BT YouView box and everything is working great all channels are mapped correctly including the internet channels.
Voice control is kinda working, but will hopefully get better before final release.
If anyone wants in, add me to xbox and send me a quick message and then I'll send an invite
Gamer tag : OhFeck360