Functionality is good where everything is on one platform. Being able to have multiple groups for different topics is definitely an advantage. The to-do-lists, attachments and adding the relevant members to different groups is beneficial.
I think Zenzap's functionality is very good, with everything in one platform. I like that multiple groups can be created for different topics of conversation. You can add to-do lists, attachments, and the relevant people involved, which is really handy. The setup was good and quite self-intuitive, similar to WhatsApp's layout and features, which helps since many people already use it naturally.