I have installed Ubuntu 12.04LTS (32bit) on my Asus EEE 1015PN. I have installed the VGA-Switch von Mtron too (https://sites.google.com/site/mtrons/projects/eee1015pn). The problem is that in Windows I get 6-7 hours running time on battery and with ubuntu I get only 4-5 hours.
Another problem is that when Windows is Idle the fan from the netbook stops whereas in ubuntu the fan never stops running. The temperature is in Windows 38°C and in Ubuntu 51°C.