Ranked in these QuestionsQuestion Ranking
Pro Manages sudo permissions (root/user/none)
It manages sudo permissions (root/user/none) in a nice color-coded interface based on projects. You can manage more than one server in groups.
Pro Very reliable across multi-cloud and intermittent connections
A single self-hosted installation or Userify Cloud can manage your user accounts in multiple clouds or your own datacenter. All that's needed is HTTPS outbound from your managed instances.
Pro Installs instantly
The shim (their agent) installs in the blink of an eye. The server takes a lot longer (about five minutes) but only needs one command to install, so you can walk away and come back.
Pro Built-in recipes for Ansible, Chef, Puppet, Terraform, Bash, and CloudFormation
Lots of built-in recipes make deploying pretty fast, and just adding a single server is pasting a one-liner that takes a few milliseconds to install.
Pro Can handle tens of thousands of servers in a cluster configuration
Handles thousands of servers hassle-free using an AWS EC2 cluster.
Pro Color Coded Dashboard
Instantly shows who has access to what server groups in color (red for root/sudo access, green for regular user, and white/none for no access.)
Pro If central servers go down, you can still log in
Even if the userify servers go down, you can still log in with your private key.
Pro Available in self-hosted and Cloud, in single-server and clustered modes
Cloud is available for free up to 20 servers, while self-hosted is limited to five servers free.
Pro Key Generator
Generates private keys, including both Mac/OSX/Linux RSA keys as well as Putty keys, and can even distribute those keys to end boxes (useful for automation accounts.)
Users are isolated in what they can see. If a user doesn't have access to a server group, project, or company, they can't see any of its parts -- not even the project or server group names or who has access.
Pro Built-in Key Scanner
Scans for unused keys (what Userify calls "loose" keys) and presents them on a per-server basis within each server groups. No additional configuration is needed, it just works out of the box.
Con Only up to 20 servers are free (10 on self-hosted)
Only up to 20 servers are free.
Con The Userify shim doesn't yet support certain containers
Containers that don't run an SSH server don't support the Userify shim (of course, container hosts are fully supported)