My playgroup has been really enjoying dipping their toes into Masks and Halcyon City Herland Collection was a great addition to the game with playbooks they could take on and tons of plothooks and lore. The vast majority of the book gives great ideas for handouts and storylines that you could pick up for your own table to challenge your heroes and then it presents a set of new playbooks in order to be able to play new types of heroes. My group picked up the Newborn and the Redeemed to add to their superhero team and they brought some really fun themes to the table as an addition. Both the lore/hooks and the playbooks have really helped open up the options and ideas for the world of our game.