Microsoft released Visual Studio 2013 Preview 2 days ago. I installed it on a development machine side by side with Visual Studio 2012 Ultimate edition. On VS2013 installation dialog box, I decided to install all the features that are being offered as part of the preview release. Since I heavily use SQL Server Data Tool in all my projects, I decided to install that also. Everything worked fine with new projects created in VS2013. When I tried to open as existing VS2012 project in VS2013, it complained when it tried to load a database project. The error message mentioned that project is not compatible with installed data tools. If you are running into same situation, here are some recommendations based on my personal experience.
I will post more updated as I do some more evaluation of VS2013