Comment 10 for bug 309792

I have the same issue.

URxvt.letterspace fixed the problem partially, fonts still doesn't look as good as in other (gnome and non-gnome) apps.

I just switched from Archlinux to Ubuntu. I was using urxvt for years on Archlinux and was rendering my fonts fine, the same way as the rest of the desktop.

I don't think letterspace option is needed here. If it works fine on other distros without this patch then it should be possible to make it work on Ubuntu. Maybe it's some configure/compile time switch/option related to Xft?