I LOVE TEAM SUMMER B SO MUCH. SO MUCH. I love the emphasis on the fact that, as you say, everyone has something to contribute, and so, for example, stuff like Matsuri's people smarts are just as important as Summer A's survival skills. (I had to start liking Semimaru after "SOYBEANS!!!" He was just SO EXCITED.) The Fuji ship arc may be my favorite in the series, although the Hana-Fujiko-Chisa ladyfriends arc is also pretty great.

I feel like the Summer A backstory and Zombie Shelter arcs were kind of the darkest point of the series, and while there have been dark points after that obviously (PUPPIES! :() the general tone after that has been a sort of slow climb to the light, a rebuilding -- Autumn and Spring and the non-murderous elements of Summer A starting to form a community, Summer B finding as much joy they can in everything, various members of Summer A starting to learn that it might be okay for them to find joy too.