I had the flatbed experience on CO 527 IAH-PHX this Wednesday.
(My folks that flew LHR-IAH BF today did not, go figure )

Anyways, the FAs and passengers spent most of the trip experimenting with all the buttons.

Good news is that I didn't try to crush my spine unrolling the bed, like I did the first time I was on Virgin's Upper Class!

Bottom line - I really liked it.

The only tiny downer is wheeling your rollaboards off the plane afterwards, there's a bit of a chicane to navigate....