I also tried 11.04 (natty) with xorg-edgers which serves the latest git xorg stuff, an I had the same results as Michael shows on page 2 in his review. I run an HP LP2465 via DVI, my board is an Asus F1A75-M Pro. FGLRX 11.7 didn't work well for me as it repeatedly crashes when I watch VDR (DVB-S) via kaffeine/xinelib and switch channels or choose another video source inside VDR (like AVIs from hard disk). After re-login kded4 utilizes one CPU core at 100%, systray gets slooooooooooow. I had the same phenomenon (X crashes when switching channels with VDR/kaffeine) with FGLRX years ago when radeon wasn't stable with my older HD 3300 IGP. Still unsolved it seems.
So I threw out FGLRX and edgers, went back to the original xorg and radeon packages and upgraded to 11.10 (oneiric) alpha 2, current state.
And - surprise surprise - Radeon works!
One major drawback though: the driver and KMS "see" a VGA monitor (on "VGA-0") which isn't there and it's configured to 1024x768. That one is the primary monitor, thus the real monitor on DVI ("DVI-0") is set to mirror the VGA and also runs at XGA res. There is at least one work-around though: in KDE System Settings -> Display and Monitor, which calls xrandr at login time. A little tricky though as X hangs when fooling around too much with the settings. The way it worked: I first set 1920x1200 using krandrtray (a systray tool), started systems settings/display and disabled the ghost VGA monitor, set the whole thing as standard. Kwin now calls xrandr at login time to apply these settings. The result in ~/.kde/share/config/krandrrc is:
Problem: while booting, when KMS kicks in, my screen switches off. And comes back after KDE-login so I have to use auto-login. Which I do on my home machine anyways. It can be set to lock the screen after login for the scared amongst us
StartupCommands=xrandr --output VGA-0 --pos 0x0 --mode 1024x768 --refresh 60.0038\nxrandr --output DVI-0 --pos 0x0 --mode 1920x1200 --refresh 59.9502\nxrandr --noprimary
I'm sure this can be done in xorg.conf too, but I want to stay with the standard graphical tools until radeon/kms are fixed. Also kernel parameters might do the trick, I saw older documentation and the switches didn't work for me. I think I tried "video=DVD-0:e video=VGA-0:d". Maybe it's the syntax with two times "video=", didn't try.
So, everything works for me now, idle power was 5 watts higher when I last measured so I guess the GPU power management lacks behind FGLRX's, but 3D works, 3D desktop works (after first reboot with new settings), but is slower than FGLRX of course. But rock stable. Btw, V-drift is faster than FGLRX only because many effects (like reflections) are inactive when running it with radeon.
So, that setup works fine for me now. And if Oneiric breaks temporarily (only, hopefully) on it's way to release, I have a backup and also a running Natty copy with FGLRX, my data sits on a RAID and my mails on IMAP
Oh and DarkFoss: Llano has two memory channels of 64 bits, populating four DIMM slots only hurts power draw (at least), latency, max freq.