For me, SVN has many advantages over TFS even when pricing is not a matter:
- SVN can be installed on old machines; it requires just few mega bytes of hard disk. It also does not need additional resources like MS SQL.
- SVN has a very larger user community than TFS.
- SVN is common in open source world but TFS not.
- SVN can work disconnected, and supports patches.
- More companies use SVN than TFS (near me).