*Yawn*
Your experience must be a couple of years old. Download Ubuntu 10.04, burn it on CD and then boot that CD on your Mac and see that magically everything "just works" - faster and more stable than Snow Leopard.
Installing and running Ubuntu Linux on COMPATIBLE hardware has become as painless as installing and running Mac OS X on COMPATIBLE hardware. And amazingly enough, Apple Macintosh hardware is fully compatible with Ubuntu Linux. It's actually easier to get Linux running on a Mac than it is to install Windows on it.
Yawn back at you. I'm writing on Debian with > 10 years experience running Linux and even greater with NeXT->Apple. No, not everything just works and is faster and more stable than OS X 10.6.
And yes, you do know w/o Debian there is no Ubuntu.
I love Debian as my second platform, but no, OS X is not behind Debian Linux, or it's Desktop Environments [KDE 4.4.5 presently and GNOME 2.30] aren't any where close to OS X for ``it all just works.''
The endless rants between Nvidia's proprietary binary blobs and the Nouveau driver will save us are just one example of a the battle of Xorg [X-Windows] which is a far superior Windowing client/server model than WindowServer. How AMD isn't fast enough with it's open source driver initiative is another humorous waste of time.
One example of a common technology vastly implemented differently and to what extent on Linux vs. OS X:
The lack of system-wide OpenGL 2.x enabled Desktop Environment [KDE 4.4.x/4.5.x and GNOME 3.x are not system-wide OpenGL 2.x enabled, but are 1.4 enabled for compositing of windows and more with plans to move everything to 2.x and eventually 3.x for KDE 4.7 time frame--within 2 years from now.
http://blog.martin-graesslin.com/blog/2010/07/next-generation-opengl-compositing-in-4-6/ ] will grow even farther apart when OpenGL 3.x is system-wide within OS X when it's OpenGL 3.x compliant.
The average consumer rightfully complains about not having 3.3 or 4.1 OpenGL drivers installed, but don't grasp that Apple is the only vendor for OpenGL that is hardware accelerated system-wide, not just at the game or other application specific level.
As LLVM 2.8 is upon us a much greater rate of switching even in Linux from GCC to LLVM will take place. With Clang 2.8 on the verge of C++ parity and C++0x features almost complete [w/ their own libcxx to replace libstdc++], more and more projects across the industry are porting their applications and platforms to build against LLVM.
Even Debian FreeBSD is happening at a solid pace to offer the latest FreeBSD as an alternative to Linux.
Options are great. In proper context makes them even greater.
Primtime
Is Linux ready for prime time consumer consumption? Yes and No. Does it have the ``just works'' of OS X? No and never will. Does it `almost just work' for a seasoned engineer, developer, multi-systems knowledgeable user? Yes.
Whether it's OS X, Windows or Linux, if you bring into the equation being able to work with developer tools, manage your network beyond point and click by requiring multiple systems with a DMZ, etc., you are no longer a Consumer, but a Professional.
Knowing both systems is a must for a Professional. Those systems are both OS X and Linux.