Just to bump the issue: sometimes, with certain font size/text combinations I have similar artifacts - even with the default font:
For development this isn't much of an issue, but this wouldn't look good on a finished project
BTW: I don't think Laurent is really using github's issues to track bug reports like these, or is he? Should I submit an issue there?
And for the record:
I'm on an updated Linux Debian Squeeze x64, running on a core 2 quad processor and nVidia GeForce GTS 450 GPU. And using the latest SFML 2.0. I will gladly provide more info if needed.