the original is horrific for a lot of reasons, they captured the oppressive summer, because well it was filmed in the middle of it, the looks of shocked disgust on the cast members, that wasnt acting, the leather face costume, well the actor had to wear it for all the shooting, in the middle of summer for week and it couldnt be washed, the actor in the wheel chair, well hes apparently a nice guy in real life but got so into the role the cast hated him.
as for the film itself, it created the splatter genre of films, its raw, full on, some crappy low budget 70's acting and was one of the first horror movies where most of the action was shown during the day not at night.
that said on its own merits the remake is a great film