I've written quite a bit about how hard we worked in this release to improve the TFS installation process.  All through the pre-release process we tracked success rates and issues using telemetry.  In every release (beta, ctp, rc, etc), we tried to learn and get better.  Once we RTM'd that telemetry became "opt in" rather than "opt out".  However we now have enough data reported to give some semi-statistically significant success rate data.  At this point we've had a few hundred users agree to share their install data (I expect many times that have actually installed TFS).

We look at the data in many ways.  In my mind the most important is "Initial success rate".  How many people succeeded installing TFS the first time they tried?  This is the best overall indicator of how well the docs prepared them and the installation program enabled them.

In our 2010 release, the initial success rate has been 97.3%.  Compare that to a 92% in the RC and numbers in the 70's for TFS 2008.  I'm incredibly happy with that number!

The next most important number is the "eventual success rate".  That means you may have tried and it warned you that something was not configured properly, you changed it and tried again.  You kept following the setup program's instructions and ultimately got it working.

In the 2010 release, the eventual success rate is > 99%, compared to 97% in the RC and 80's in TFS 2008.

It's early and I hope to see more data but both of these numbers really indicate to me that we've done a good job making the overall installation and upgrade experience a lot better.  I do still occasionally see reports of people having difficulties but it's good to know that the vast majority of people are having a very good experience!