I did something I normally don't do but I was curious what the result would be because I have been thinking about starting brand new with Vista and Office 2007 on the work laptop. Last night, I backed up my current XP SP2 install onto another hard drive for safe keeping and attempted a Vista in-place upgrade.
I fully expected it to fail. Previous beta in-place upgrades typically resulted in disaster. It looks like they made a lot of headway from RC2 to RTM with regards to in-place upgrades. The only thing that is non-functional on the Thinkpad T60 is the built-in Sierra Wireless MC5720 EVDO modem. The XP drivers work "mostly" except that the actual NDIS portion of the driver refuses to load. I'm guessing IBM/Lenovo will be posting OEM drivers for Vista soon for the EVDO card soon because, in general, Sierra Wireless has been a very good vendor for Vista drivers.
The current Vista ATI X1400 are a bit flaky and I'm tempted to drop back to the MS drivers that came with Vista. I've never liked the .NET Control Center application anyway so that isn't a huge loss for me. It is everything a .NET application shouldn't be.
Other than that, every application I had installed previously works great and the system in general is faster, I suspect, due to how multithreaded the kernel has become. It really does seem to take advantage of the dual core CPUs better. Even with all the fancy options enabled, this system flies.
The built-in Bluetooth support in Vista is working well with all my BT devices so far. I did make sure to uninstall any application or driver that I thought might conflict with the upgrade beforehand, so that might be why this upgrade is working so well. I miss some of the features of the WIDCOMM/Broadcom BT stack, but the built in support seems a little less clunky.
The only other thing that is partially working is the thumbprint/biometric device. Technically the drivers are functional but the Lenovo GINA hasn't been upgraded yet to support logon/logoff events yet.
So, honestly, unless I run into some major issues, I doubt I will be starting out on a "fresh" copy anytime soon.