i can vouchf or this. having taken over our IT department a few months ago I was asked to consolidate a lot of machines and to basically get it smaller and more manageable.
so far two ipcop machines have been put in place, for proxy+web filtering+vpn (so that is three other boxes in the bin) and freenas has found a home with us also, as a storage server and internal ftp, using ghost4linux to back up important users machines when necessary.
we are a ms OEM, action pack subscriber and a microsoft gold partner. we do not have to pay for ms licensing, so the cost isnt even an issue.
next will be the exchange server, probably into the nearest bin, as well as the external customer facing web and ftp machine. I've got a few workstations using various builds of linux to see if it is feasible to roll it out to select users instead of our current xp.
ek voel niks.
ClarkConnect
Zimbra for exchange.