Excited from the high recommendation toward endpcnoise.com as a Linux vendor I hastily browsed around at the endnoise.com site to find their words about their dedication toward Linux and all the values of freedom associated with it as discussed here. Finally I had to make Google's site-search. The best I could find was this:
On the page there is quite hallow asterisk in the end of first clause. Scrolling the page down all the way to bottom you'll get:
"*All systems, including those with Linux or without an operating system installed are built a stress tested under Microsoft Windows. If Linux or no operating system is selected Microsoft Windows will be erased after stress testing has completed successfully. We can only provide limited support Linux operating system problems."
Of course offering Ubuntu as option is better than mainstream of vendors can do, what I can tell, but still I wouldn't call this a Linux hardware vendor offering hardware stress tested as equally or, preferably, better with Linux than with Windows. There isn't any word, whether the components they use in their assemblies are assured to have decent working drivers in Ubuntu as in Windows or do they happily sell you a system with Ubuntu, but they don't make any claims that e.g the graphics card works beyond very basic fb-driver offering only VGA resolutions.