I used to read these a long while ago! I stopped at some point because it was starting to feel repetitive -- no, actually, I just remembered exactly where I stopped and why: it was after David's plane crash, when there was all this melodrama about how he almost died and then an issue or two later, it felt like it didn't matter at all and hadn't affected any of the character relationships. I just kinda threw up my hands and decided I needed to stop reading for awhile.
... having said that, it's gorgeously drawn, and I love the characters and all the experimental stuff he does (the prose/art mixed pages, the songs, stuff like that). I think this is one of those cases where I just needed a break from it, and always meant to go back to it, but kind of wandered off to other things and never did. I still have all my old GNs, though, and one of these days I'm going to go back and FINALLY find out how it ends!