My HD2 cell phone gain the time. 4.3'' 800x480 ppi display, 1GHz processor, all facilities like Wifi, GPS, SDHC cards are the properties of new cell phones but also the characteristic of my two years old HD2. The best part of this cell phone is the set of operation systems which you can deploy to this device. Windows Mobil 6.5 was the original, Windows Phone 7.5 Mango is now available since yesterday as well as various version and customizations of Android . Note that you can also install MeeBo and Ubuntu to you HD2 but it doesn't seem as a common use-case. I'd love to share my feeling since I've used Windows Phone 7.5 Mango for a week as well as I'd like to compare it to HD2's Android. HD2 and Windows Phone 7.5 Mango I've started to use famous Yuky Back to the future ROM having basic Windows Phone 7 system available to standard upgrade via Zune. Simple instalation followed by mentined updates brought my phone into pre-release Windows Phone 7.