There are quite a few improvements that Windows Phone users have been asking for. Those improvements may not seem appealing to other OS users, but they're well appreciated by the customers for whom they're intended.
Some of the common goodies here are:
*The action center (which is called notification bar in Android) has been added.
*The ability to set a wallpaper as metro background. You can now also add an additional row of live tiles if you need more apps on your main screen.
*Improved multi-tasking (apps are suspended instead of being terminated, and apps can be closed by sliding down similarly to Android)
*Keyboard now support Swiping (and it works really well)
*It now support File-Manager with full view, play & management options (it's not built-into the OS though, but you can download the official Microsoft File-Manager app from the Windows Phone Store)
*The Music and Video player now supports streaming content, so you can stream your content via them.
*All built-in apps have been upgraded with more features. Be it the browser, camera app or the music, video, store, etc.
*New built-in features have been added which give handy options. Such as a battery saver, wifi sense, storage sense, etc.
*Personal Assistant called Cortana has been added to the OS which works like Siri except it's functionality is currently limited due to it being in beta.
*Dual-SIM support has finally been added.
*Additional UI tweaks have been applied at certain areas which are minor but improve experience.
^ And that is not even the complete list, there are some more things added or improved in the OS. Read the official release notes for more info on that.