I can’t decide…
- Seems to have more .NET projects than GitHub
- Integrates seamlessly with Visual Studio 2012 source control
- Presents a “front door” to the project
- Seems to be talked about more than CodePlex
- The vibe seems to better aligned with code samples
- Gists (although I would prefer something that worked directly with the code repository)
…so I am using both for now.
Learning Tools 
I couldn’t find your user on GitHub, so I presume you ended up deciding to go for CodePlex somewhere along the line.
That’s right. At the time, Visual Studio was better at working with the TFS interface in CodePlex. A lot has changed since then…it may be worth a second look. On the other hand, if it ain’t broke, why fix it.