Most PRM's are great for two things; push communication like email blasts or distributing assets, and distributing commissions payouts.
Partnerhub covers finding partners, activating them, ongoing communication, project collaboration, document sharing, one-time rewards, automated messaging / alerts, and tracking referrals.
Some of our users keep a simple affiliate tracking solution so they can generate custom tracking links and pay commissions to those ghost affiliates who simply want to add their link to a blog post or youtube video to collect commissions. Day to day management of partners is done in Partnerhub. If you have yet to pay out commissions, read this >

Yes. Free for both user types forever. Tech teams to have a valuable partner opportunity for agencies, apply or be invited. But, once in, Partnerub® isfree. It's our opinion that no one should have to pay to partner.

Here is our research (last updated March 2022): 

Yes. You can invite team members as Admin's or Member's. And, you can bulk import your entire roster, or add them one at a time.

Partnerhub has been described by users as a dating app for partnerships. It serves recommendations to the agencies based on overlapping customer profiles. The agency has to make the first move, but once approved, either party can create tasks, add the partner to a project, chat...