This is true, however Windows suffers from the same problem (and OSX too, however in a minor degree).
> awful font rendering
Only by default maybe. I did tweak my fontconfig (just some symlinks available in /etc/fonts/conf.avail) and IMO the font rendering in my Linux systems are better than my Windows systems (even after tweaking Windows ClearType).
There is the fact that some applications does not support fontconfig, however I can't think anyone that I use daily at least.