HP Touchsmart tm2 here, and not everything works well. It has hybrid graphics (Intel chip for low power, and ATI for more graphically hungry applications) and Ubuntu 12.04 still cannot make any use of the ATI card. Worse, the ATI card is powered together with the Intel GPU at start, making the battery run out very fast and the laptop overheat.

This can be fixed with vga switcheroo, but it's really not an optimal solution. Net, avoid hybrid graphics laptops, usually they don't work well with Linux.