I had problems updating my 10.5.2.Zephyroth install. My system wouldn't boot after 10.5.3 update. I preformed a fresh install with LeoforAllV3 ran AU .5 and it worked fine. I have lost QE but i installed the latest nvinject added my device id to geforce.kext and everything was working again. I also installed the latest AMD 9.3.0 without any problem. I don't actually notice any major improvement, but I'm happy my system is fully updated. I may start to use my Hackintosh for fun now. Hopefully we'll be fine with these updates for a while.

My Specs
Asus A8N32-SLI Deluxe 2GB ram Evega 8800GT