Definitely one of the reasons to purchase the Google Nexus 5 is to lay your hands on the Android 4.4 KitKat. Google has introduced a lot of new features with the KitKat OS but there are a few significant changes which I would like to share.
1. Unlimited home screen panels: Now you can create as many home screen panels as you like and fill them up with shortcuts, folders or widgets.
2. Support for integrated pedometer: Soon FitBit could be history, as the Nexus 5 now has sensors to support pedometer functions which are enabled through apps like Move in KitKat.
3. Google voice control: Although it is not as rich as the Moto X voice control, the Google search voice control capability lets you control your device from the home screen panels.
4. Immersive mode: Reading books would be easier as you can now hide everything but the text. There are not many applications available but there would be in the near future.
5. Caller ID by Google: Now apart from your phone contacts, you can search for a caller in all businesses listed in Google Places and also through all other Google Apps as well.
6. QuickOffice integration: Google had acquired QuickOffice a couple years ago and now it has integrated it into the OS.
7. Google Wallet without carrier restrictions: Google has removed NFC carrier restrictions from the Waller so now you should be able to tap and pay with a Nexus 5 on any carrier.
8. Album art on lock screen: Another feature that is a nice touch is the ability to see your album art while controlling your media right from the lock screen.
9. Integrated print support: You can now connect to any printer with the integrated printer support.
These are just some of the prominent new features introduced. Definitely there would be many more which would be highly useful according to your usage.