Thats the BIG problem with FOSS drivers generally. Thats why Windows conquer the market share.
Lets say that you are a regular user (you bought your notebook with Ubuntu 12.04 pre-installed for example) and you have Intel graphics.
Then lets say that a new game released on Steam and you want to play it like the way you would on Windows. Your drivers are 2 years old and they will not update as long as you don't upgrade to a newer (not that stable) version of Ubuntu.
Thats why I think Nvidia is the best choice.
I have a GTX 460 on Ubuntu 12.04 and I have played TF2, Wargame European Escalation, HL2 and L4D2, maxed out settings, without problems just like I can do on Windows.
On the other hand on my HTPC I have a Radeon 2600 PRO that lacks the performance of Windows driver and even if you forget the performance regression you get, the worst is that in most cases graphics are corrupt (flickering, shadowing problems, glitches etc)
fglrx is not even supported any more (staying with 12.04 LTS would be necessarily for that hardware).
So Intel graphics should try to support with one-click updates the most popular distros (Ubuntu, Fedora) if they want same quality support with Windows.