The new Maps app seems pretty nice - though I have not had the chance to fully test it out yet. Phone has some nice new options that will surely be beneficial. YouTube does not come installed, so you will need to grab that from the App store if you want to utilize it as an App. Outside of those items and the new light blue color that Apple is using in all Apple apps, I had not notice anything that got me all too excited yet. That is, until I upgraded my Mac to the latest version of Mountain Lion.
Messages Finally Makes Sense
When Apple released the beta for Messages in OS, I took it out for a spin. It certainly is clean and has the iOS feel to it, which is great for consistency across all devices. However, I was limited to using either my iChat screen name, or my Apple Me email address. While this is nice for syncing across my iPad, computers and iPhone, it did not integrate my iPhone phone number - so I was left with multiple separate conversations from the same person in different places.
It turns out, Messages in OS X put the foundation down for the release of iOS 6. When you upgrade your device to iOS 6, you are given the option to add your cell phone number to be used in Messages iOS. This holds true for any device running iOS 6 including iPad. Even better, with the latest upgrade in Mountain Lion, you can add your cell phone number to be used in Messages OS. So now, you can have your iMessages sent using your cell phone number synced across all devices whether it is your laptop, iPhone, or iPad.
It is important to note that your messages will only sync across the board when sending/receiving iMessages (shown with the blue background) - not SMS messages (shown with the green background). Meaning, that if you get a text from a friend on a Samsung Galaxy S III, that message will not go to any other device outside of your iPhone.