The short story is this. If you are accessing Windows 7 from your MSDN subscriptions, save yourself time and frustration by installing the Windows 7 Beta, not the Windows 7 Beta Checked Build. See available downloads here.
This past weekend, I decided to upgrade my work laptop from Vista Enterprise to Windows 7 Ultimate Beta. I was unable to upgrade from Vista Enterprise to 7 Ultimate because that action is not supported. I then tried to upgrade from Enterprise to 7 Enterprise, but I was unable to upgrade from a staged build to a non-staged build. I decided to repave entirely, choosing Windows 7 Ultimate Beta, and I tried to do all of this on a Friday afternoon, two hours before leaving.
I installed Windows 7 Beta Checked Build (x86) - DVD (English), last updated on January 14, 2009, from my MSDN subscription. I did not install an internal build. Instead, I decided to go with what is publicly available via MSDN.
Why did I go with a Checked Build? Because I failed to read the details describing it. What it cost me in time and frustration, I gain in valuable learning experiences. So it was not a total loss. I received a number of buggy issues with the checked build, mainly the inability for Windows Update to properly download all of my necessary updates, including my video drivers and smart card reader, where the latter enables me to remotely access my work domain.
I gave up and decided to download and install the Windows 7 Beta – DVD (English). Everything works great. I was able to get online, download all of my updates, and connect to my work domain. No issues found so far, and no annoying assertion error popups.
My favorite Windows 7 feature so far (non-UI related) is that PowerShell 2.0 is installed by default. PowerShell 2.0 provides more functionality for remoting, among other enhancements.