As a Kurosawa partisan, I was watching closely in this for any signs of fealty to the greatest Shakespeare adaptation ever. They were there. First there's the billowing mist that obscures the battle under the opening credits in Polanski's film, and that reappears at a key moment later; this seems a clear homage to the memorable fogs in Kurosawa's version. Then there's the way Polanski frames King Duncan's first approach to Macbeth's castle. In Throne of Blood, there's a wonderful shot where the Macbeth character watches riders approach his fortress - a long shot, where we watch the riders approach from the distance, zigzagging through the fields toward us. In Polanski's film, our vantage point is the reverse: the camera stands at the king's shoulder, and stays there watching him ride across the heath toward the castle - zigzagging as he goes.
So Polanski knows who to respect. But is his film good? Well, sure. It can't avoid the trap that many Shakespeare adaptations fall into, of feeling wordy (Kurosawa's film benefits by deciding not to stick closely to the original text - it's less a matter of him making the film in Japanese than of him deciding not to call it Macbeth). But it is very visual, and very effective.
The look of it surprised me a little bit for how undaring it was. It looked exactly the way people in 1971 seem to have been imagining the Middle Ages, which is to say like an only slightly dirtier version of the film Camelot. Still ornate and pretty enough to make later audiences, accustomed to Terry Gilliam's innovations, smirk a bit. I guess I had expected a bit more of a radically modern sensibility. But the unexpected lushness of the settings probably worked to make the bloodiness, and bloody-mindedness, of the action more shocking, and that, I think, was the point of the film. (As Professor Wikipedia points out, Polanski's interpretation was Jan Kott's.)
But more than the blood itself, it was the oppressive lighting effects that I think I'll remember - the red filter in the opening shot, and the red stained-glass window in the Macbeths' bedroom.