It is very good indeed. The cinematography is not perhaps particularly special, but it is certainly worth a big screen, and works as a film, not a TV special. I don't think (speaking as a republican, or because I like a bit of pageantry, an elected monarchist, no reason for us to have to have a president just because we don't have a hereditary monarchy, let's go back to the old days) that it is as royalist a film has been suggested. I can see the argument on that side; on the other, I can see the argument that modern-day monarchy warps everyone it touches and simply isn't worth it.
Performances: Colin Firth as Bertie/George is excellent - I am not a stammerer, but his stammer seems convincing to me. Geoffrey Rush as Logan likewise excellent. I am a great admirer of Rush as an actor. Helena Bonham-Carter's mannerisms for once do not irritate me, but work as part of the performance. Jennifer Ehle is impressively unidentifiable, though I cannot comment on her accent. Guy Pearce is fantastic as David/Edward, though if I never see Wallis Simpson in another film/television programme it will be too soon. I felt rather sorry for the child actor playing young Princess Elizabeth. She's perfectly adequate, but she's up against Karen-from-Outnumnbered (Ramona Marquez), and thus doomed. It's not simply that there is something about Marquez that make her look like the child-most-likely-to-become-an-axe-murde
I was not, happily, around at the time, but it didn't really strike any false notes in terms of period (OK, Logan obviously doesn't actually live in that sort of area, but I'll allow for dramatic licence). Well, there was Churchill. It wasn't really Timothy Spall's fault that he looks like a man doing an impression of Churchill - it's that there is absolutely no reason for Churchill to be in the film at all, least of all playing an utterly ahistoric role. I'd love to read an AU novel in which Churchill has managed to get Edward VIII crowned and then had to deal with having set a Nazi sympathiser on the throne. But he's unnecessary, inaccurate, and perhaps as a result unconvincing in this.
Amused by the reference to Prince John - no way he'd have been name-checked were it not for Poliakoff's The Lost Prince (oh how I wish Gina McKee had been cast as Bellatrix). It's Henry I feel sorry for, though. Thick as a brick, and so boring he never makes it into a costume drama.