I have tried several other client portal tools on Appsumo and found Clinked to great for my use case. It was the only tool that allowed creation of subgroups that automatically inherit the content from the main group. This is great if you have several groups or teams that you want to keep separate but that do need the same content to start from, such as in corporate training, and change programs. I use it in procurement, where all vendors received the same information but are not able to see each others names, teams and proposals. The interface is fairly intuitive. More important: my clients actually use the portal.