I didn't expect to like this movie, given its period, headline subject matter etc. But don't let those factors put you off, there is real depth and some top notch scenes in this surprisingly superb movie.
Max von Sydow, Gunner Bjornstrand and Ingrid Thulin are three of Bergman's most consistent quality performers and all three have major roles in this film. There are a fair number of stereotypical character parts, mostly performed by ensemble quality character actors. Bibi Andersson is capable of far more than her giggly girl part enables her to show in this film. Indeed, there is some comedic material in this film reminiscent of Smiles of a Summer Night, but don't mistake this movie for one of Bergman's less masterful light pieces, this has real depth and substance.
There are some amazing bits of cinematography, especially the early scenes. The pacing of the movie is masterful, as is the clever use of parallels in the story - the failed actor "dying" and then reviving is a prelude to the pivotal incident around Vogler's "demise".
Top notch scenes include Mrs Egerman opening up to Vogler - she seems so lost - also both scenes in which Bjornstrand's character (Vergerus) insists that he was not taken in by the "magic".
This is now in my Bergman top 5, which makes it a "must see" in my book.