The Cities of Sigmar Battletome expands on the Free Cities established in the Season of War worldwide campaign + fleshed out in the (honestly really solid) Firestorm map-campaign-in-a-box supplement. It's also the only battletome I've purchased a Limited Edition of, and it's... kinda worth it. The cover art is purdy + the bookmark ribbon is surprisingly handy; I've considered gluing them into all my normal Battletomes now.
After listening to the designer's commentary on the Warhammer TV Twitch stream, they made a conscious decision to focus on the Firestorm cities instead of a more generic, design-your-own approach. I'm kinda bummed about that, but after the neglect Free People received for so long, anything is better than nothing. Currently, the only major Free Cities are in the realms of Ghyran (life) and Aqshy (fire), (Excelsis in Ghur aka beasts from multiple Black Library novels, is absent).
I happened to be kicking off a Path to Glory campaign shortly after the Battletome dropped, and since an all-Steam Tank army is viable now, I decided to start an army based on an industry mogul in the Ghyranic city of Graywater Fastness using defense contracts to fund his own private army...
Ricki Smith has also done some very interesting work in a similar vein with his Midnight City project by working from "what would happen if the old Empire clockwork horse aesthetic was dialed up to 11"...
So yeah, definitely excited to get back to painting my Lavender Hill Mob union-buster boys now that Animosity is over and I can actually hobby again.
Alex