What are the alternatives for setting up a common directory and accounts?

We have a network of 12 machines and one server at the moment connected by a gigabit switch in a single room. We want every user to be able to log in and use their account on any machine, as well as being able to execute mpi jobs where each machine appears identical. This implies mounting a common home drive and managing accounts.

I know NFS from way back. I just tested one that I suspect is insecure.

/etc/exports

Following the directions for Ubuntu's NFS configuration does things the old way. But I saw in the exports file gss/krb5i which leads me to believe there is a secure, encrypted way to do this.

We also found freeipa which seems to be a complete packaged solution. But it's difficult to know what the other alternatives may be. Can anyone point to an overview listing alternatives, or state from experience a good secure way to achieve common user ids and files across a network?

Thanks!