I want more people to find this group so bad.
This question is sort of redundant but at least it can get some conversation started.
I think everyone would say the architecture design/setting/scope of this manga is the most beloved. I personally love how Nihei designs his characters. Silicon Life are so perfectly horrific with the way they look and their goal to wipe out humanity. I also love the constant of still expression Nihei puts on Killy. I can recall maybe twice that Killy looks pissed. All other times his features look monotone or unmoved by what's going on around him.