One nice thing is iCloud integration. It's not Mavericks specific, been around since Lion, but very handy.
I did a clean install of Mavericks. All of my notes, contacts, calendars, Safari settings, and keychain stuff imported from iCloud. Mail settings came over too, not sure if that matters as I copied my Mail folder from the backup anyway.
Heh.. I never knew it was Delete. Just checked...Delete woks in Snow Leopard. Delete is only one button. I always used "Command - [" which is what it says in the drop down menu. Where did you come up with Delete...lol. Thanks.