Originally Posted by Licaon
AIGLX sucks for performance reasons. Try running at 2560x1600 or 3840x2400 and then have 50 windows open. Now try playing a video with transparency or moving wobly windows around or do the translucent cube and watch the lag. Even on a high end video card this chokes with AIGLX or using KDE's composite stuff but can do several hundred FPS even on a 8800 GT with XGL.
The simple fact is that with XGL I can still get several hundred FPS in this situation and non-XGL lagged to crap. For much lower resolutions and much less windows AIGLX worked ok but that simply isn't the case for how I use my system.
This has actually been what has kept me from totally upgrading my distribution. I use sabayon based off gentoo so I can still update individual packages without any issue but I doubt I will upgrade my entire OS anytime soon as I have yet to see anything that matches XGL and XGL pretty much became deprecated.