Premium gives you the best web experience, especially when using a high-speed connection like broadband. You can only access the Premium version by using Internet Explorer through Windows.
NOTE: You will automatically connect to the Premium version by using Internet Explorer through Windows. If you don't want to use Premium, you must select OWA Light when you log on.
Light is the best choice if you use a dial-in connection because it offers less features and is therefore faster. If you connect using a web browser other than Internet Explorer through Windows, you can only get the Light feature set.