I'm a librarian who loves anime, manga, and reading a wide variety of genres.
Nostalgia tempts me to get the full thing - Battle Angle Alita was one of the first manga series I ever read. However, my manga reading tastes have changed significantly since then, and I'm not actually sure I'd enjoy the series now. That leaves the lower tiers. I remember reading The Ghost in the Shell a while back and disliking the amount of text Masamune wanted readers to wade through. The first volume of Inuyashiki was unpleasant and, judging by reviews, it only gets worse from there. The first volume of The Seven Deadly Sins was generic fantasy and an enormous amount of boob grabbing.
That leaves the first tier, with Ajin: Demi-Human. I've seen a good chunk of the anime, and as long as it follows the manga fairly closely, I'd say Ajin would probably work reasonably well for me.