Feb WinFx CTP changes
The Feb WinFx CTP has introduced quite a number of changes, you should be aware of Karsten's list, Tim's list and these two forums posts I started on layout changes and for things not yet noted. The Orcas WinFx bits seem to be really misbehaving in this release, from having to retype XAML lines to get the editor to play to having to use Clean\Build almost all of the time. You may also notice render differences in this release, values don't appear to be as progressive in their effect and you may have a lot of tweaking to do. I am in my 5th hour of refactoring to this CTP.
Update: the layout changes noted above should be carefully noted, see Rob Relyea's follow up to my post.