As Falk said, we've been doing tests for nearly a month. The production version isn't much different from the beta one, in all aspects. So just read Falk's blog, you'll see what the new K7 is capable of
To just answer some of your Qs, AF is definitely faster, especially w/ non-SDM lenses. It's much more decisive under low light. But this isn't the biggest thing to me. The biggest jump to me is: the super quiet shutter and much shorter shutter lag. You need to try it to see the difference, it's not like a Pentax camera in these regards, and I've used many Pentax cameras from early manual ones to the latest AF ones
After playing the testing K7 for 2 weeks, I just couldn't get used to the K10D, not for the IQ but for the shutter. This along is worth the upgrade imo.