Rubbish
There are so many fawning over-excited posts about the quality of this adaptation I feel like I have to redress the balance. You can disagree, but hopefully I can offer an alternative to the blatant Welles worship and pre-warn people interested in quality film versions of Shakespeare's plays. It's films with acting like this that give Shakespeare a bad name.
1. The accents in this version are utterly laughable from nearly everybody. Roddy McDowall and Dan O'Herlihy give their best Irish accents. Interesting that Welles cast his own son as Macduff's child, meaning the little fellow is playing piping American against his "Scottish" mother.
2. Everyone is over-acting their little socks off. It makes moments that should be dramatic and powerful incredibly silly. You could argue that in '48 this was the acting style and is acceptable; I'd disagree. Welles performance on stage was probably pretty impressive - but on the screen it's too large, and too overwrought. All opportunity for detail and subtlety is lost. Great speeches have stupid pauses and are frequently mis-emphasised confusing their meaning. (e.g. (*employ silly over-modulated 'acting' voice and roll a few 'r's) "the multitudinous seas incarnadine making... the green... ONE red."). It makes sense reading in the trivia section that the dialogue was pre-recorded and the actors mimed to their own tracks - it explains why everything is so stilted and "performed". No one is getting to do any proper acting on set at all.
3. Lets not mention Macbeth's funny crowns. Oops, just did. The Statue of Liberty is possibly worse than the square cardboard one. Probably shouldn't mention Ross' Red Indian pigtails either. *snort*
4. The cutting of the play in this version is ridiculous. Some may call it "cinematic" but it actually destroys all the ebb and flow of scenes that work extremely well as they are - Shakespeare wasn't exactly a slouch when it came to dramatic structure. I can understand a cut or movement of dialogue to improve sense or make a dramatic point. Most of these changes just seem to be whims, and often are nonsense. (one example of many... immediately after Duncan is found murdered Banquo delivers what is meant to be his soliloquy suspecting Macbeth's hand in the deed - to Macbeth himself... this makes no sense. A man prepared to murder a beloved king in his own castle and is due to be crowned king himself is probably not the best person to reveal you know is a murderer. Deeply stupid.)
There's no denying it looks beautiful and is shot extremely well (which tends to always be Welles' prime interest) but the bad cutting, bad accents and wide-eyed portentous melodramatic playing belongs in the dark ages of Shakesperean acting. Watch it with the sound off, if at all.