Yes, me too, I noticed very sluggish response until I ran "--disable-font-backend".  But now, when I specify --disable-font-backend I get a message in the *Messages* buffer:

command-line-1: Unknown option `--disable-font-backend'

On Thu, May 15, 2008 at 2:20 AM, Sven Joachim <svenjoac@gmx.de> wrote:
Since the font-backend merge `emacs -q' pauses for several seconds
before the splash screen is displayed.  Anyone else seeing this?

Sven