Miller dresses his cast like Victorians, rather than making them look like animals (after all, he says in his commentary, the typical way of doing Alice is to take big stars and then cover them up with animal heads so you can't see who they are).
He takes the book literally. For instance, the Hatter and the March Hare are mad in a real way rather than the typically overblown cartoonish way. Peter Cook's Hatter is soft-spoken, laughing and agreeable, his lines always sounding like non sequiturs; while Michael Gough's March Hare is defensive, suspicious, and genuinely troubling.
The best scene, which probably best captures what Miller was working for, was Muggeridge's Gryphon and Gielgud's Mock Turtle. The fey White Rabbit of Wilfred Brambell ("A Hard Day's Night") is a delight. Peter Sellers, appearing all too briefly, has an amusing bit of business (Miller in his commentary doesn't like it but it suits the scene admirably and in this case Sellers the slapstick authority knew what he was doing better than the director -- the scene cries out for what he does). Michael Redgrave is phenomenal in his all-too-brief turn as the caterpillar, but the scene is damaged by truncating the poem "You are Old, Father William" to the point that it makes no sense on any level. Peter Cook's Hatter is engaging at first but his one-note madness is quickly tiresome. More interesting at the tea party is Wilfred Lawson's Door Mouse (watch his hands -- he knows his business); and Michael Gough ("Batman"), who has an aura of danger.
The pros in the cast all do their best, and no fault can be found with the big-name stars who are doing good work for peanuts.
Miller's concept of Alice is the primary reason the film ultimately doesn't work. The girl he chose as Alice has a very interesting face, and is wonderfully untraditional. Sometimes her delivery (heard half in voice-over and half in dialog) shows promise. But Miller, probably to accentuate the dreamlike fixation, has her walk through the movie like a somnambulist, not becoming involved. The little emoting he does allow is almost always to show Alice's rudeness. For the most part her facial expression is fixed and unengaged, and this is Miller's fault.
The cutting from scene to scene is abrupt. Part of this is probably Miller's continued obsession with the working of dreams, and partly because a lot of transitional material was cut out at the request of the bigwigs to make the show move faster. And because Miller is quite literal with Carroll, he makes the mad tea party actually have the monotonous languor of people trapped in a long afternoon tea that will never stop -- and it becomes tedious.
Oddly, on the DVD, far better than the movie is the director's audio track. Jonathan Miller gives a full 80 minute's description of what he tried to do (and what price limitations left him able to do); and when the movie is seen in that light, it makes a lot more sense. Sometimes Miller explains why things were done, sometimes he desperately tries to justify what was done. In all cases, his commentary is interesting and he never falls into the trap of describing what's going on, but always why it's going on.
The movie looks good, and individual turns by actors are superb, but the whole is less than the sum of its parts.