Reason 1: Philosophy
I simply got tired of seeing microsoft throwing disposable technology to just remove support, deprecate or whatever afterwards. Release "free" stuff and then, you know what happens...
Time for quoting some early microsoft employ, one of the original heads of Direct X division, let's look at the roots of this:
This is all great stuff, you have a perfect plan. Developers who are reasonable should all support it, but what do you do if none of this works.
What do you mean?
What if in spite of your best efforts, your best arguments, you best relationships, you can't get them to support them. How do you force the industry to support Microsoft anyway?
Force them? Well, I don't know.
Come back when you have a plan that answers that question.
That perplexed me for a long time. I'm thinking, "What the hell does he mean, force them? I can't hold a gun to their head, so how do I put all these companies in a position where, regardless of what they see is in their best interest, they have to adopt your technology?"
That experience had a major impact on my thinking.
I realized that a major part of my job was to figure out how to use technology control to create economic force, or leverage, such that money and business flowed in Microsoft's direction, and people had to go [to them]. That, ultimately, is when I became a "Microsoft guy," when I got that concept.
Well, I'm more aligned with GNU than that. I'm also tired of learning how microsoft likes to play the good guy to screw everything up later. I think now they're trying to play the good guy in the open source space... such a joke!
I'm happy to see a come back of the OpenGL, in the past I felt sad seeing graphics on Windows evolving purposely not supporting OpenGL and the alternative for the rest of the world stall. Those days are now gone. The world has changed. Mobile graphics matter. I'm just trilled with the SteamOS announcement by Valve, it may shake things up in the gaming space, I already play some games through Steam, but availability still doesn't compare. And last, but not least, OpenGL is active again.
Talking about announcements, I've also pledged for the Ubuntu Edge. Even if it doesn't catch, Canonical proposal of convergence is more coherent, contrary to microsoft tentatives till now.
Reason 2: Sincerely Friendly
I started computing on Windows, and spent most of my programming career working on it, even developed drivers, and by now, almost abandoned it.
In the meantime I used linux distributions in rare occasions, because of job related stuff and to my surprise, started finding stuff I missed on Windows, or which I even had no idea existed, like multiple workspaces.
I then bought a macbook pro and initially found it quite nice, it got a decent shell, contrary to Windows which has its very limited command prompt, or the much late powershell, which is quite a weird creature in the shell world. I found OS X touchpad gestures awesome, and it also had multiple workspaces, which I find so useful.
Anyway, I started to miss the friendly environment I was looking as a developer. Much late to the game, homebrew started a great job on packing tools for easy build and deploy (I never liked MacPorts). As time passed by, I got convinced that nor OS X, nor Windows, were first class citizens as development platforms for what I was interested, which is to play with and use a lot of programming languages and open technologies. You know, I'm writing this post using VIM, Jekyll, Git, Linux, Ruby, Github... I'm in the right place for this kind of stuff.
Because of its completely non-*nix inheritance, Windows aways gets late on support by interesting open source initiatives and projects. Its culture runs around distribution of tools through binary blobs, instead of sources. I can't fix them myself if needed.
I view the way Windows is, as a two-way barrier in itself, which may initially provide technology lock-in, but that in the long-term can promote its own irrelevance.
I turned my macbook pro into a tuxbook pro:
How do I compare it to OS X on usability?
Better font rendering, out-of-the-box (on a macbook pro 13"):
Font on Ubuntu Raring Ringtail
Font on OS X Mountain Lion
Font on Windows 8
I really dunno how to get OS X to display like Ubuntu, I tried to tweak its font rendering...
Better workspace management. I got a 3x4 wrap-around workspace grid.
Very customizable, with VIM-like keybinds for workspace switching and also, with touchpad gesture bindings. I find this much better than OS X Mission Control.
I must note that, at this age, Windows still doesn't offer native multiple workspace functionality. All alternatives for multiple desktops I've tried, were broken someway or another simply because Windows has no proper native support for this.
I didn't expect to be able to customize touchpad gestures like this, and that it would work. Switching to Linux I just expected to get used to scrooling through scrollbars, and just use the keyboard to control windows and workspaces. Not just that, I have 2-finger drag for vertical and horizontal scrooling, 4-finger drag for workspace switching, both horizontal and vertical, and 5-finger pinch to see all windows from my current workspace.
"Apps". Well, for how long linux has had package management? It just got somewhat profitable with the inclusion of additional application centers, like on Ubuntu. Application distribution on Linux is mature and way better than what I find on OS X and Windows. It bundles homebrew and the Mac App Store in one single thing. There're packages for sources, not just binaries.
I get a better shell, a better VIM... well, the list goes on.
For what I'm looking for, I have facts, Linux is better. Window management? better; gesture customization and support? better; development in general? better; font rendering? better. Of course, development for iOS should be better on OS X, as also, development for Metro applications should be better on Windows.
Reason 3: Longevity
Can you realize that the open source initiative has the potential help of the entire world?
That power can't simply be dismissed. The open source model makes anything harder to get killed in a global scale when things start to be adopted. It's technology, knowledge, know-how, that you invest, for the long term. The world has changed, communication and collaboration around the globe is much more empowered now, this can only add value to the open source model.
Reason 4: Respect and Fun
Free in Linux and GNU is not about free of charge solely, it's about user's own freedom, to tweak, customize and pimp his own system, and have that right safely guarded, which, on some users view, is a lot of fun.
Reason 5: Ubiquity
Last, but not least, do I have an option for not using Linux? Even my Sony Bravia runs it.