I spent a little time in the last week playing with the December CTP of Visual Studio 2005. Specifically, I was hoping to use it on the chapter I was working on for my book.
The has been a lot of refactoring going on by the Windows Client team between Beta 1 and Beta 2. Unfortunately some of that has been downscoping and removing features. A lot of stuff has been renamed as well. It looks like most of those changes are in this CTP, so if you want to see something more representative of what the RTM will look like, and a lot closer to Beta 2, then this CTP is good for that.
This does not appear to be a very stable release from a Windows Forms development perspective. Just putting together a couple simple data binding scenarios resulted in a bunch of exceptions for things where the designer was doing all the code writing, so it wasn’t a lack of understanding of the programming model on my part. So if you want to actually write any significant apps or samples in Windows Forms, I don’t think you will want to do it with this CTP.
My strategy for the chapters and samples in my book is still to keep developing on Beta 1 for now, keeping in mind what is changing in Beta 2 (which can be explored with this CTP), and plan on doing a port of everything to Beta 2 as soon as it is available.