I'd pick SVN. I've worked with SVN from a developer standpoint before and I currently work with TFS, and let me tell you that TFS is painful. While TFS is feature full and is more than just version control, its version control is sloppy at best. Merging is horrendous and many of us now turn to manual merging or merge tools because we can't rely on TFS. Files go missing, aren't downloaded to the local system sometimes, and there are just oddities in its behavior that make you want to bang your head against a desk.
That being said, if you want TFS in all its glory, are willing to work with its pain points, it is a great tool to setup automated builds, and releases.
