Zoom? Better? Maybe to have a videocall.. but add a couple hundred users to a call .. and you start hitting limits. Granted, those are not very common but I think the killer feature of slack and teams is discoverable channels. Dont get me wrong Teams UX and performance is terrible in MacOS the whole experience is like taking a school bus to a freeway.. but feature-wise is very complete IMHO and it can handle 500+ user video calls with no problem.