We are with 6 developer and currently use Visual Studio 2008 Professional with SVN and Visual SVN. As soon as vs2010 is released we will upgrade from vs2008 pro to vs2010 premium.
However if Team Foundation Server has a proper source control included in vs2010 premium, then it does make sense to use it. We like SVN, but like tight integration of tools even better.
On the internet information on SVN versus TFS 2010 seems to be scarce. Hence my question here.
EDIT: This video looks very compelling. Is this marketing talk or real?
Thank you all for your replies! I absolutely appreciate this. A little more background info.
This is our current stack; vs2008 pro, Visual SVN, SVN, Jetbrain Teamcity. My main problem is that we use a lot of tools from different vendors which more or less integrate. Sometime more, mostly less. At least it takes a lot of time to set it up correctly.
We currently do not use branches, but we want to. Therefore we have to set up SVN from scratch (we looked into it carefully). So let me rephrase my question: Should we set up SVN or start using TFS?
If you are a Microsoft shop, then TFS is a good fit.
If Subversion does everything you need, would you fix something that is not broken?
You have to have a reason to change.
[I use TFS at work and it works great, with very few problems. I use Subversion at home, simply because I need less infrastructure].
Update [2012/05/01]: If you are not a Microsoft shop, then Git and mercurial would now be the tools of choice.