I've not seen every version of The Phantom of the Opera so I cannot pass judgment if Hammer's effort is indeed the best on offer. What I can say is that for 85 minutes I was entertained. In general I love Hammer films though there are still too many that promise much and pail off towards the end. Kiss of the Vampire and The Reptile as examples. But I feel Phantom keeps you glued to the movie, even if you can guess what will happen at the finale.
The Phantom himself is played by the great Herbert Lom, who gives a stunning performance acting with one eye. His presence is felt and it is the subtle movements he makes that gives the film its menace. Michael Gough is also wonderful as the crooked and downright evil Ambrose D'Arcy. Thorley Walters is here too as is Heather Sears as the opera singer. Edward de Souza plays the producer- and he just about pulls off the role. There are some subtle comedy moments and this is a typically gothic entry from Hammer.
Watch out for a tasty gore scene and cameos from stalwarts like Peter Troughton and a very tiny one from the excellent Michael Ripper as the taxi man.
It seems that reviews for the film are mixed on here. I have no idea why, I thought this was a Hammer classic, and is well deserved of its 5 stars.