Cloud question

Sync will behave exactly as it always has. Except it can do it over Wifi in addition to over USB cable. Backup will backup all of your personal data (app info, mail settings (not mail itself if you use iCloud mail or another IMAP service), calendar (same as mail), contacts (ditto), etc...). Personally, I like using the iCloud backup because once iTunes Match starts, my phone will no longer be linked to a single computer rather a single library

Edit: The iTunes Match part is related to the automatic download feature. Upload/download via mobile device or any computer using my home sharing library and get it anywhere. Also applies to ripped CDs.