As to whether or not it is an official release, I haven't a clue. But, as to differences, I have noticed several on my HTC Mogul (HTC xv6800, Titan, whatever you call it). Most notably is speed: the device is *noticably* faster running the same problems, and I have run 6 or 7 different ROMs with WM 6 to compare against... it is by far the fastest. Also, on the titan voice command w/ bluetooth headset hasn't ever completely worked, as the verification never worked. All bluetooth functions on my phone seem to be working significantly better.
Other than that, there are a few changes... seems like it's automatically closing certain programs when they aren't used (notably PIE and Messaging) about which I have mixed feelings, but it does tend to make for better memory management...
so there are some improvements. I'm still identifying all of them, since I just flashed the new OS night before last, but there are some definite changes.