Phoronix checked out the performance of Ubuntu 12.04 for ARM, you can check it out over here.
Last week I delivered benchmarks showing how Ubuntu 12.04 is
ARM-ing up for better performance with ARM-based hardware and detailed
some of the plans Canonical has for this architecture going forward.
While those benchmarks last week illustrated some significant
performance improvements with the Ubuntu 12.04 stack -- in large part
due to the switch to hard floating-point support -- the gains are not
over. In fact, there are already some striking improvements if using the
Texas Instruments OMAP4460 SoC as found on the PandaBoard ES.