There's all the stuff that makes it look better, but will not matter because we have Sense, then there's this:
Android 4.4 takes system performance to an all-time high by optimizing memory and improving your touchscreen so that it responds faster and more accurately than ever before. This means that you can listen to music while browsing the web, or race down the highway with the latest hit game, all without a hitch.
The future is calling
The new phone app automatically prioritizes your contacts based on the people you talk to the most. You can also search for nearby places and businesses, your contacts, or people in your Google Apps domain.
A smarter caller ID
Whenever you get a call from a phone number not in your contacts, your phone will look for matches from businesses with a local listing on Google Maps.
All your messages in the same place
Never miss a message, no matter how your friend sends it. With the new Hangouts app, all of your SMS and MMS messages are together in the same app, alongside your other conversations and video calls. And with the new Hangouts, you can even share your location and send animated GIFs.
//Hopefully this will make Hangouts good. They have the user base; now they just need to make Hangouts reliable.
Print wherever, whenever
Now you can print photos, documents, and web pages from your phone or tablet. You can print to any printer connected to Google Cloud Print, to HP ePrint printers, and to other printers that have apps in the Google Play Store.
Your office, anywhere
Create and edit documents, spreadsheets and presentations from your phone or tablet with the newly redesigned Quickoffice
Chrome web view
Applications that embed web content now use Chrome to render web components accurately and quickly.
Device management built-in
If you ever lose your device, you can find or wipe it with the Android Device Manager
On devices with an infrared (IR) blaster, Android now supports applications for remote control of TVs and other nearby devices.
Step counting built-in
When you use fitness apps like Moves on Nexus 5, the phone acts as a pedometer to count steps. Android 4.4 and updated hardware make this a more battery-friendly way to measure your activity.
Tap to pay, built a new way
Android 4.4 introduces a new, open architecture for NFC payments that works with any mobile carrier, and lets apps manage your payment information in the cloud or on your device. Now you can tap to pay with Google Wallet or other apps at more than a million stores.
That's what I'm excited about, anyway.