This tool mainly differs around how identities are structured and how the evaluation works.
Identities represent specific entities in your application. For example pricing plan can have it's own identity, organization users belong to can be separate identity, users themselves are represented as identity objects.
You define as many identity types as you need through the interface or the API, then create actual identities through the API from you server-side application.
Now the flags evaluation part is where it differs from most other tools, as you define the hierarchy at evaluation time.
Let's say you have Premium product identity, Mailstorm Inc. organization identity, and Alicia end user identity. Alicia belongs to Mailstorm Inc. organization which is subscribed to Premium plan.
When Alicia is using the app, you could evaluate feature flags for her by sending following identity IDs: premium_id, mailstorm_id, alicia_id (order is important)
For each feature flag evaluated it will then take the first override it encounters among the provided identities, or fall back to the default environment value.
This gives a lot of flexibility and control on flag evaluations.