You don't know what portable means do you? portable does not mean you can do it from many places, portable means it ports to other environments. You're statement should read "You can login to any windows machine on your network", its not portable.
Don't need any more portability than that, it's a WINDOWS application.
Please understand that in IT portability does not mean you can run it from any windows machine you choose..
It's not going to change how anybody does business. There is no savings.
How much time to put in an upgrade on 1000 desktops? how much time to put in in on two serves?
You can log into 80% of the desktop world, that's portable.
Please understand that in product USE portability means the the number of computers a user can use.
Depends on how the machines and your network are setup. I can take an hour to setup everybody's NT account (actually you setup the groups not the individual accounts) to push down upgrades when they logon, most Windows versions now default to automatic upgrade so unless you change it the IT department spends zero time doing those upgrades. Harware is tougher, but at least the entire company isn't shutdown while we upgrade the hardware, just who ever's hardware is being upgraded that particular minute.