I have used every version of Apple's iOS from 4-6. I have used Android Gingerbread, Honeycomb, Ice cream Sandwich, and Jellybean operating systems. In less then 24 hours of use on my new HTC Windows Phone 8x I am convinced that it is the most socially integrated mobile device on the market.
That is my opening statement :)
After seeing one of my classmates using a Windows Phone over a month ago, I began looking into the OS. Just my luck Microsoft was launching Windows Phone 8, and Nokia and HTC were coming out with two stellar phones using that OS. I decided that I would get a Windows Phone, and so I spent the next few weeks researching and here I am today with my new HTC Windows Phone. It does have some flaws, just as all OS's do.
-Complete Facebook integration
-Text and fbook chat in the same windows similar to iMessage on iOS
-See Facebook and twitter updates on the contact itself
-Check-ins and posting to Facebook and Twitter are seamless and simple
-Grabs all your contacts from each source you give it, and links it all together
-Does a much better job at linking contacts then Android or HTC ever has done
-Polished User Interface
-Beats Audio (phone specific)
-Great looking phone
-No VPN support (uses Direct Access which is a direct SSL connection)
-I haven't found a way to statically assign IP settings
-No detailed battery report (Android wins in this department)
-Lacking in app support for the moment
This is by no means a comprehensive list, however this is what I have found in the first 24 hours.