I don't care much about shiny new OpenGL specifications met, or fps figures going up in newer releases (as long as the chip in question is able to render a decent desktop environment, that is). After all we are talking about bread and butter graphics chips.
I've come to enjoy the comfort of configurable-free, fast-switching KMS. It doesn't look so good though on external displays connected to closed-lid notebooks. It all worked great until after 2.6.32, when suddenly after some acpi-lid detection policy change my X200s doesn't choose the native external display resolution anymore. Also at some point external display detection (with DVI-DP adaptor) stopped working at all. Probably that isn't a common enough setup to be well-tested, who knows? Anyway, there's a bug open including a patch that I need to apply to any kernel since 2.6.33 that reverts to my desired behaviour: https://bugzilla.kernel.org/show_bug.cgi?id=27622
I've got two stationary setups for my ThinkPad X200s (LVDS native 1440x900):
-) X200s closed-lid startup @ Ultrabase [DP] -> [DP] Eizo (native 1920x1200)
Resolution ALWAYS wrong* without patch, Detection works (mostly)
-) X200s closed-lid startup @ Ultrabase [DP] -> [DP]->[DVI-D] -> [DVI-D] Lenovo ThinkVision (native 1920x1200)
Resolution ALWAYS wrong* without patch
Detection completely non-functional, only BIOS-detection immediately at startup works. If I miss that fraction of a second, I can reboot all over again, and the Lenovo BIOS is really, really fast. I've become really good at this though, but it's still about a 30 : 70 to fail at first boot .
* Resolution always wrong basically means that console output is aligned at the upper left corner and limited to the size of LVDS-native, while in X the LVDS-native resolution is blown up to the full size of the external display, looking gross.