I flew BA First Class earlier this year LAX-LHR-SIN-MEL-SIN-LHR-IAD. While I haven't flown SQ or CX First Class since 1987 and so can't compare their current product to BA's, I quite enjoyed my flights with BA.

Here are the two trip reports, complete with menu transcripts, that I wrote on those flights if you're interested. Hopefully, they may shed some light on what to expect.

http://www.flyertalk.com/forum/Forum81/HTML/002707.html

http://www.flyertalk.com/forum/Forum81/HTML/002544.html

It's worth noting that in terms of spaciousness, sitting up in the nose of BA's 747s seemed less cluttered than sitting anywhere in First on the 777. Also, on the 747 you're so far forward of the engines that the flight is much quieter.

So far as I know, BA doesn't operate the 777 on its routes to the Far East so you should be fine in that regard. Really, try and get the 747 wherever possible.