Hello...
I have in total, 2 graphic novels and they are by Clive Barker, they are:
The Yattering and The Jack (from the books of blood - volume one)
Revelations (from the books of blood - volume four)
Saint Sinner, which is a comic, I have three parts out of seven, unfortunately discontinued.
I enjoyed reading all of the above. If they are written well and none of the original story is missed graphic novels can be brilliant. The artwork can be amazing, so much time and effort has went into it. You still get the essence of the story, I have to admit I was pretty skeptical when my husband gave me my copy of 'The Yattering and Jack', I am a big fan of the books of blood so I thought there was no way they could portray that story into a graphic novel but they did and I enjoyed seeing The Yattering in living colour, so to speak (it was how I had imagined him but a different colour).
I think graphic novels deserve as much merit as a written novel, a lot of work goes into it.
And speaking of comics, I have a fair collection of 2000AD's