Yes, I'll throw my hat into this group too. Bash is fine.

YMMV but I have found using zsh too frictitious to be helpful. Sure, theoretically zsh living in a bash world (lets face it, all scripts are bash) is completely fine but reality seems to differ. Copied a one liner from shell history into your script? Crash. Use arrays? Weird bugs. Use shell builtins? Whoa unexpected interactivity!!! Etc...

Bash is absolutely fine as a default shell. As an added benefit, you don't feel like an invalid once logged in to a container or server.