Gantz' quality goes up and down pretty hard.
When he was starting out, he had no idea how to create like...any sort of meaning behind anyone's death. He just would half-build a character and kill them off. The Buddha Temple section almost made me stop reading. After that, it was pretty boring. Then we get the new team made out of pure fucking awesome, and it picks up again. But then we get vampires and random deaths that ALSO don't make any sense or have any meaning when they occurred. When I finished Phase 1, I had no real desite to read Phase 2.
On the other hand, it has a bunch of great sex scenes. Hallway sex is my personal favorite. Too bad she dies.