I hate Mozilla Firefox being so slow on Ubuntu, so today I tried Swiftfox and it feels faster. Not as fast as my old Gentoo build without damn gtk support (I use kde), but it's an improvement. You can try it yourself:
echo "deb http://getswiftfox.com/builds/debian unstable non-free" >> /etc/apt/sources.list apt-get update apt-get install swiftfox-$YOUR_PROCESSOR