Earlier quoted context omitted.
VS 2008 here, somebody apparently tested 2012 but nothing came out of it with people fearing that a different C++ compiler will break everything...
I think the improvements we'd get in Entity Framework performance, testing, and analysis would be well worth it.
Technically, that's not a VS2012 or 2013 feature, that comes from .NET 4.5, which you can use with VS 2010.
However, the testing and analysis is well worth it. I don't know what your source control is, but paired with TFS 2012, it's a pretty large productivity improvement for my team over VS 2010 (as large as you can get from an IDE upgrade).