... the one notable snag is that if you are developing Windows Mobile software, you'll be out of luck with VS2010. Redesigning Windows Phone 7 from scratch (by dumping Windows Mobile 6.5 altogether) was also reflected in the transition of VS2008 to VS2010, i.e., the development tool for Windows Mobile (in the form of SDK with VS2008) was deliberately ignored in VS2010 in favour of Windows Phone 7 development. Quite interesting to see if this was a wise move by Microsoft. If you're stuck with VS2008 (because you're developing Windows Mobile software) and still want VS2010, the two can co-exist happily side by side on the same machine (of course, subject to the usual computing resource requirements). Also the upgrade route works just fine, meaning you should opt for the cheaper Upgrade version rather than the more expensive full version (in fact, Microsoft Office, or design tools such as Expression Studio 4 Web, are as valid as V2008 to qualify for VS2010 Professional Upgrade).
As for using VS2010, it really provides a pleasant transition, say from VS2008, and equally provides a very welcoming environment to newcomers to VS2010. I know most improved features have been mentioned by other reviewers (such as the WPF re-design and nice look, .NET multi-targetting, process multi-threading, etc.) but one thing that stands out for me (and less to do with VS2010, surprise surprise) is the Help Library Manager (you can also come across via Windows SDK 7.1 installation) which allows you to download various help libraries (which you can choose) and access it locally (as well as update it from time to time). When Help is set to local, all the context help from within VS2010 invokes the local help library. Fast and neat, and you don't have to be online.
In short, same design environment as in VS2008 but much improved, more user friendly, and beautiful!