Screenshots of what you're doing.

Yes, this is mainly down to the rasterizer.
Opera for example seems to use the Freetype autohinter (like default Xonotic),
which works better at 11px, though it is overall blurrier below 12px, and has some problems of its own.



Generally, all I can do is to define hints in accordance to the Postscript Type 1 specifications.
Also experimented with TrueType, but if you have ever operated on stacks with an assembly-like language,
you'll understand the magnitude of pain-in-the-arseness of that approach.