Extensibility. What extensibility options does the product offer for platforms for which native support doesn't exist? Most consistent sign-on (CSO) products let you plug in your own scripts for replicating passwords to unsupported systems, including applications developed inhouse. But your options vary widely.
Transparency. How transparent is the application to users and administrators? Does the program require users to use a new utility to change passwords?
User-Account Control and Mapping. How does the product support user-account control and mapping? Users need to have the same user ID for each system on which they have an account, but unfortunately users seldom have the same ID. Some legacy applications prohibit users from having the same user ID. When you change a user's password, how does the system find every account for that user? How do you exclude certain accounts from synchronization?
Password Requirements. How does the application handle password requirements? Each environment can have conflicting rules for aging and content. Does the product provide a way to unify these conflicting rules?
Workstations, Servers, and Host Systems. What effect on workstations, servers, and host systems does the product have? Which systems will you have to reconfigure, and which will you have to install new software on?
Logging and Fault Tolerance. What are the product's logging and fault-tolerant features? What happens when the system goes down and a user's password changes?
Price and Licensing. Does the product's functionality support its price?