|Feature||Standard Server Edition||Enterprise Server Edition|
|Mailbox Databases||1-5 databases||6-100 databases|
|Roles Based Access & Control||Yes||Yes|
|Online Move Mailbox||Yes||Yes|
Keep in mind you also need client access licenses or CAL’s. They are sold in standard and enterprise edition. The enterprise however is just an add-on to the standard license. So for one enterprise user you must have a standard CAL and enterprise CAL. The main difference between the two is unified messaging which enterprise gives you the rights to.