FusionAuth

Pros: It has everything that you could need from an authentication platform, even extra things. The best part is that is open source and free if you manage yourself the platform.

Cons: Just to put a con, it has tons of unused features for my organization.

Overall: Nothing to envy from paid platforms. Mounting server could be a bit tricky but you can have it done in 30min if you have experience deploying servers.

Pros: FusionAuth is a clean and modern IDP. We found it very easy to integrate our systems with FusionAuth. We used the C# client and the Java client to implement the integration and followed the well-written API documentation.

Cons: Some small bugs here and there but nothing serious. For example, logging in to the FusionAuth web service sometimes fails for no apparent reason and one needs to login again. There are also some hidden configurations that weren't defined in the documentation. For example, if you want a refresh token with the login request then you need to activate that under the preferences and this was a bit elusive for us.

Overall: The overall experience is very positive and we would gladly recommend FusionAuth to anyone. The price model is fair and the integration is straightforward.