Can't comment on the new UA "F" but - regarding SQ's C -

Yes.. it is a flat bed... and a good one. It is as a seat that some folks don't like it...

It is VERY wide.. (I had to use the pillow to "buttress" myself in a bit...)

That IS a pretty minor complaint from me though! ..and I believe they are now providing a rectangular block style cushion to provide more comfort?

I had 11A.. front row of the mini cabin so no intrusion from a seat in front.... that applies to all 4 seats in 11 of course...(and in 14 IIRC)

You have to sleep at a slight angle across the "mattress"...due to the design.. again, some folks don't like that... I didn't care...

Food was excellent.. service was "SQ robotic" and a bit disjointed IMO.. or perhaps on my first SQ C flight I just expected too much based on hyperbolic reports from others??