I've actually been on RTM Mango for quite some time now, but a recent offhanded mention with no real interest behind it prompted me to prove my status as fully released Windows Phone 7.5. Two months ago I installed the developer preview and so far the only difference I can find in the RTM is the phone now says Windows 7.5 instead of WP7_5_Trial for the version. I'm absolutely thrilled to be running the latest of the 3rd most popular mobile OS with less than 10% market share. I look forward to the day when Mango officially releases to the public and it skyrockets to 11%.