The best thing about Linux is its rate of improvement. Linux in January 2010 is much nicer than a year ago and barely recognizable from, say, Linux 2003, the year when Windows XP launched. Windows and Mac OS are much slower to innovate. There are several reasons for this.
- Because Linux has many distros, it can't take a big stumble like Vista. If Ubuntu stumbles, RedHat, SUSE, and Debian keep innovating (to name just the biggies).
- There's a constant churn of projects contending for every component of Linux,from media players to Ethernet drivers. The distros continuously select best-of-breed.
- Linux has a huge developer base, comparable to the whole Microsoft development ecosystem. Many of them aren't paid, and those who are paid are distributed across hundreds of companies. This huge developer base isn't subject to Brooks' Law because open source projects release early and often, and because Linux is decomposed into many independent but interoperable pieces.
Unfortunately, I don't think Linux will ever take over as the desktop market leader.
- Windows and MacOS are good enough for most people most of the time.
- Linux requires extra effort to get and install. Microsoft has shown repeatedly that they can keep it that way on PC compatibles.
- The network effect works against Linux on the desktop, just as it favors Linux in servers and embedded systems. Since 90% of the world runs Windows, Windows is the default choice for independent desktop software developers. Even Google, a very Linux-friendly company, released Earth, Chrome (browser), and SketchUp for Windows first. There is still no SketchUp for Linux.
- The highly innovative development process leaves too many loose ends visible to end users. Linux always needs a little tweaking (though this has dropped dramatically in the last decade).
There are some things that could disrupt the current desktop space.
- OLPC or Google Chromium (OS) both have the potential to push Linux into the majority desktop OS. Other platforms could do the same. But those platforms are so different from the traditional Unix/GNOME/KDE userland that they barely count.
- The other potential disruptor is non-x86 CPUs. ARM or another architecture could come from below and replace a significant fraction of the desktop boxes. Windows is pretty tightly wedded to the x86 architecture, so Microsoft does what they can to bolster x86. But Moore's Law is still in effect, so a disruptive CPU is certainly a possibility.
Basic usage answers: I've been using Linux on my desktop and laptops since 1998-99. I use it all the time on my primary and secondary machines. I cautiously recommend it to others. (Cautiously: I don't push Linux. Whenever anyone shows interest, I explain the pros and cons, and make sure they have an Ubuntu LiveCD in their hands when we're done and understand that there's no commitment to trying it.)