What .Net framework should my Sitecore 7.0 build target?

Question

We are upgrading a Sitecore 6.4 solution to 7.0 (release 2).

For development this requires Visual Studio 12 and .Net 4.5 framework.

Our production environment is running Windows 2008 R2, .Net 4.0 and our solution is running in a .Net 4.0 app pool.

We don't currently have any solution code that requires .Net 4.5 specific features.

So a multipart question:

What benefits are there to upgrading the .Net framework on the server and targeting .Net 4.5 in the build?

Is there a potential performance gain?

What are the potential drawbacks?

What .Net framework does Sitecore itself target?

Answer 1

Thanks to Sitecore Climber in the comments -

From the Sitecore 7.0 Installation guide:

2.1.3 .NET Framework Requirements

Sitecore CMS 7 requires .NET Framework 4.5.

Any available updates to the .NET Framework should be applied to every Sitecore host.