I updated my T-Mobile HD7 to the 7720 RTM as well. It seems pretty nice. It's also a little disappointing because now I can check my e-mail, and all my social media stuff so much more quickly than I can on my Android phone that it feels like I spend less time playing with my Windows Phone.
Also for anyone who has a T-Mobile HD7 that got the update notification after updating to 7720 can you list your Firmware, and Radio versions? I haven't seen an HTC update, but I'm wondering if it was the update that came out a few weeks ago and most people were on the Mango beta and just not seeing it. I had not been on the Mango beta, just stuck with NoDo until this came out.