Anyone ever used ezeelogin for centralized SSH gateway?

[samata]

Are there any alternatives? How do you manage SSH access by remote users in a multi-server environment?
If you have used it:

What is your experience with it?

If you haven't:

How do you keep track of your remote SSH users accessing your servers and what kind of a setup do you have? (How many servers and different users etc...) ?

I'm looking for a solution to centralize SSH user management and limit user's (help desk staff) capabilities when they are logged in to certain servers, so that they don't go where they don't need to etc...