Sometimes I use the projector which I have a 3 metre X 2.3 metre screen. Fun for showing OHP or the Animator software stuff, but doesn't have the clarity possibly because I'm only running it through a not so expensive quality "AverKey 300" external scart device. The projector is about 6 years old now, some of the newer ones these days are so much better and brighter even under light conditions.
I thought it was wonderful 4 years ago when I upgraded my small Acorn monitor to a big 17" one, though I had my eye on the 21" monitor.
I have not seen an LCD screen on a RISC OS, can the 20.1" LCD in high resolution mode produce clearer screen images under light conditions. I find that my small Windows laptop LCD can glare at times if I move too much to the wrong angles.