Reading some of the reviews for this movie below, it becomes readily apparent that the reviewers are referring to some other, later movie--- not the 1963 Hammer "classic". I'll take their word for it that whatever later film entitled "Kiss of the Vampire" they saw was awful. The 1963 version isn't.
I hesitate to refer to the Hammer film as a "classic" but it's certainly one of the better (if not the best) vampire film to come from Hammer. It was never one of the ones I saw on TV as kid (although I've read that a truncated version of it was shown in some U.S. TV markets), and it's more low-key than the Christopher Lee films, and more "believable" (if vampire films can be considered "believable").
The vampires in this film are members of a "cult" led by the charming, urbane Dr. Ravna (Noel Willman) and his 2 children. Unlike the versions with Lee (which, don't misunderstand me, I've enjoyed over the years-- but they're generally not put together well), Ravna isn't a snarling, feral creature with red contact lenses, but he does occasionally display a smiling, subdued sadism (such as his discussion of peasants crushing grapes for wine with their dirty feet as his "guests" prepare to partake) that hint at greater, more profound depths than ever displayed by Lee's sexy, sinister cartoon villain.
The human couple involved in the drama-- played by Edward De Souza (I saw him recently guest-starring in an episode of "One Foot In The Grave") and Jennifer Daniel--- are far more believable, and appealing, than any I've so far seen in a Hammer production. For a change, you'll actually care what happens to them.
Clifford Evans, filling Peter Cushing's shoes, seems perfectly unhinged from the first moment we see him on the screen. Considering his daughter was a victim of the vampiric cult, that seems perfectly understandable. And pretty Isobel Black as another innocent-turned-evil-predator is very sexy...in an Undead sorta way.
It may not be a "classic" in the same way "Nosferatu" was, but it's different and inventive and engaging, and if Hammer had made more movies like this (or "Brides Of Dracula") it may have lasted longer as a viable studio than it ultimately did.