I have to say that having used Slack for clients' projects and as part of a few political campaign teams, the primary value add is the organization of meta-information (files) in the same client as the chat service. I'm not sure I'd ever pay for that kind of service.

Also I've never clicked on a Ryver ad. I read the blog post linked here, and while I find some merit in the idea that competition must be contrasted and that we're wired to focus on conflict, the aggressiveness is off-putting.