The packaging alone is exquisite. Thick box with a cardboard band carrying rating logos and the title of the set. All four releases have original poster art and a thick booklet for each film.
I've only skimmed over a bit of the first two films. The remastered color insert is a revelation considering how awful it's looked on all previous releases. Also, the authoring on 13 Ghosts is just about the most clever I've seen for a film. If you pick the Illusion-O version, all of the ghost scenes allow you to switch between three angles: plain Illusion-O (blue and red tinting), filtered to red, and filtered to blue. On top of that, there's seamless branching that substitutes any color material for B&W (as well as omit Castle's intro).
It's a fabulous box set and the films, with their crazy gimmicks, are hugely entertaining. Excellent picture quality on all films and masses of interesting extras.
I'd only seen HOMICIDAL theatrically before. It was the first UK "X" certificate film I had seen and the tension amongst the audience was palpable during the "Fright Break". I particularly enjoyed THE TINGLER, even though the idea was daft and the whole film was structured around the Tingler seat gimmick.