I still found loading web pages in the solution painful at best;especially with custom controls, taking 1-2 minutes to load - but can be somewhat curbed if Source View is set as default. I hope they continue to focus on the performance.
If you are upgrading and previously merged web app projects together for rapid developement which you ran them on a single WebServer in debug mode - you will now need to set them staggered on different ports. It appears VS2008 prevents the binding of multiple web projects to the webserver but it will work.
All devs upgrading will need to install this patch in order to get the benefits the dev speaks about in this video though. It is a must install.