It's hard to untangle this from book 17 in my mind, as I finished the last half of 17 and all 18 in one mad rush last night.
Plenty of action. More than usual for the books, and it was really exciting. Closure on a lot of fronts, with a little bit of uncertainty at the end, just to keep us on our toes. I enjoyed meeting two characters that we'd been curious about.
As always, the struggle between Johan, Tenma, Nina - and their ethics and morals - was engrossing, and I was really taken with a few of the panels - Urasawa can really pour it on when he needs to.
Ultimately, a fitting end to the series, which I can't recommend highly enough.