Windows and Android functionality. I use a Windows computer for some limited amount of things, and it's invaluable for me. Also, if you use Dropbox syncing, the Dropbox folder has some javascript magic that makes it work as a web app (decryption happens client-side).
On the other hand, the new keychain access will have direct Mobile Safari integration.
Sync- it's possible with Keychain Access + Dropbox, but not seamless
Easy password generation- no switching to Keychain Access, copying, etc.
iOS access- up until iCloud sync, passwords were not easily transferred to devices
Support for Windows browsers
Form filling- Keychain will do addresses, but not credit cards