A matter of perspective, a matter of solidarity...
There are several issues here which should be considered.
First, with any commercial OS, the main advantage is that there is usually one single, major 'big picture' driving force behind all the considerations in the OS, in terms of the feature set, user interface, and target market(s). The bad part about any of the Open Source Movement or Free Software Movement projects is that there is no real solidarity and no real driving focus, with the notable exceptions dictated by tradition: effeciency, security, stability, and multiple-user capable.
Linux (and the various commercial UNIX projects before it) have a proud tradition of being "written by geeks for geeks" and as a consequence, the people involved largely didn't give a d@mn how easy to use something was, since the attitude is that "anyone who's going to use this is going to take the time to learn everything about it and probably peek at the code". And this was probably 100% true until the Linux movement circa '97-'98.
I am a Mac user and have been one since 1985, when I first touched a nifty, neat-o Mac 128K and 512K at a computer expo in my home town. Anybody who has used a Mac any real length of time gets spoiled, I suppose, with Apple's UI and their high standards for a lot of things, nonetheleast of which is the user experience. Plug in a device and it just works. Install an app and it just runs. IRQ conflicts? Heh. Driver conflicts? Heh. Can't use the modem and listen to sound files at the same time? Hah! Filenames can only be 8 characters long? The OS can only deal with more than 640K of RAM by way of patching itself around the issue to bridge higher memory?
Anyhow, I've toyed with Linux on and off for probably 8 years now, and I'm running it full-time on a Shuttle XPC I built, and have been for the best part of the last 2 years now. I'm using it right now to view this message board and type in this thread. There are many areas in which Linux needs to be improved what I would classify as "drastically and substantially". I would point out though that Linux is to the Operating System what PC Clone Makers are to the x86 hardware world. You have lots of variations, some inconsistencies, but a much greater ability to innovate.
Now, I'm not going to sit here, as a Mac user, on a Mac forum and try to advocate that all of you Mac users need to give up your Macs and embrace the penguin, but to say "it's inferior" without even so much as a second thought really doesn't do it justice.
Besides, it's thanks largely to open source that we even have Mac OS X. In a very real way, had it not been for Linus Torvalds and the people who do the BSD UNIX stuff, Apple may well have picked Jean-Louis Gassee and BeOS instead of Steve Jobs and NextStep cum Mac OS X.
Did you know right now that, for instance, there are groups working on products which, if they are followed to their logical conclusion, stand a chance to go toe to toe with QuarkXPress, InDesign, Illustrator and Photoshop? Specifically, I'm referring to Scribus (DTP), The Gimp (painting and image manipulation), and Inkscape (vector-based illustration work). Did you know that Adobe is getting into Linux and the Open Source movement?
I doubt very much that Microsoft will ever do anything to completely unseat Apple on a technological basis, but I strongly believe that the Linux community may indeed be that very threat to Microsoft and Apple, in time.
I would also point out that I find Flash 7 to run much better on my x86 Linux box (and, though I hate to admit it, on the Windows boxes I have to use at work) than on any Mac I've used it on. In my opinion, that's just inexcusable.
Just my 2¢...
