12.04 has been the single worst release ever for me (used Ubuntu since 2006). These include the Nvidia binary driver crashing, the open source Noveau driver losing the plot and drawing random content from the wrong windows, a 2 minute wait booting a laptop waiting for network, compiz move window making life hard but disabling is even worse, sound applet not showing up, repeatedly disabling my webcam microphone for no reason, massive increase in power consumption and the list goes on.
The binary drivers or the nouveau ones? I've always used the binary ones, and Nvidia's driver quality has been why I've only bought Nvidia cards for many years. It has only been this release that caused me problems, and even then I finally solved them by downgrading the Nvidia driver version.
I tried gtkperf to see what figures I get. I did note that the results depend on the size of the window quite a bit.
On my workstation with an 8800GT I got 3.46 seconds at default window size and 4.08 at 1920x1200 (using mutter window manager). On my 5 year old laptop with Intel 965 graphics I got 7.30 seconds (using metacity).
I switched to Chrome years ago and its tab switching is fine.
