I've hooked up my Freeview HD (UK) box and got the preview update/Smartglass. I'm very, very impressed. The ability to be in-game and say "Xbox go to BBC One" and it actually ignore the SD channel and put you straight into the HD channel is simple bliss. Then after finishing that, saying "Xbox, go to Forza Motorsport 5" and it kicks off exactly where you left it is just beautiful.
The ability to browse the TV guide on my phone while the TV is still dedicated to the channel is awesome. Love it.
How did you get the preview? I really really want the one guide to work!