Font quality

I have the strangest problem with font quality using Xft. Fonts in GTK+ apps 
(which don't use XFT) are noticibly higher in quality than fonts in KDE 3.0 
apps (which use Xft through Qt 3.0). In KDE 2.x, I could get KDE to stop 
using Xft by disabling anti-aliasing. However, Qt 3.0 apparently now uses Xft 
all the time, with or without anti-aliasing. Either way, the problem 
shouldn't exist. The quality of Freetype 2.x (which Xft uses) is supposed to 
be identical to Freetype 1.x (which is used by core X). Rendering fonts 
directly with the Freetype library supports this assertion.

I'm running Debian sid with custom compiled KDE 3.0, GNOME 1.4, and Freetype 
2.1.0 with the bytecode interpreter enabled. I've seen the exact same problem 
in several other configurations of Mandrake and Slackware. Attached is a PNG 
showing the differences I am talking about. The segment at the top is a 
screenshot of KMail displaying the alphabet in Monotype Arial 10pt. The 
bottom picture is a screenshot of GEdit displaying the same text in the same 
font. The letters that differ between the two are pasted along the bottom, 
with KMail on the left and GEdit on the right. 

Any help in understanding why these differences are there would be 
appreciated.