Parece que a correspondência de fontes estava errada. Isso funciona:
<!-- Special handling for Droid Font family -->
<match target="font">
<test name="family" qual="any" compare="contains">
<string>Droid</string>
</test>
<edit mode="assign" name="hintstyle"><const>hintfull</const></edit>
<edit name="antialias" mode="assign"><bool>true</bool></edit>
<edit name="rgba" mode="assign"><const>rgb</const></edit>
</match>
<!-- Special handling for Ubuntu Font family -->
<match target="font">
<test name="family" qual="any" compare="contains">
<string>Ubuntu</string>
</test>
<edit mode="assign" name="hintstyle"><const>hintnone</const></edit>
<edit name="antialias" mode="assign"><bool>true</bool></edit>
<edit name="rgba" mode="assign"><const>rgb</const></edit>
</match>