Ah, thanks for the link!
I do find that I prefer Linux for development work. But a large part of that is that I've been using Linux for years and know it well enough to customize it to work the way I want it to. I use Gentoo, so I essentially build the system from scratch using exactly and only the components I like set up exactly the way I want them. It's a much more difficult and complex install/setup, but in the end it works exactly the way I want it and so is even easier to use for me; I can't stand using distos like Ubuntu just because they're designed to make it very easy to work in a particular way (which isn't the way I want to work) and they're aren't as easily customizable (though Ubuntu is a fine choice for probably the majority of users). They always feel like they're getting in my way.
There are certainly aspects of OS X that I think are far superior to anything available on Linux (almost entirely due to the enforced uniformity of environment), but I find that those things are generally not things that I care about when working: I like a simple, minimalistic work environment which is very easy to achieve with Linux (I use XFCE with bits and pieces of Gnome sprinkled in where they fit my needs such as Nautilus for easy integration with Dropbox and gvfs, and gnome-do as a quicksilver replacement). I also think that the fact that Linux is community developed means that it has a lot of nice touches that really only benefit or appeal to developers/hackers built-in. Another big part of why I prefer Linux for some things is probably just that I love to tinker, I'm certainly not the poster boy for 'desktop Linux for grandma'.
Originally I switched to Linux from OS X for work because I was spending more time working on my laptop and my MacBook's 13" screen was just killing me, but a MBP was more than I wanted to pay. I was able to sell the MB for enough to cover the cost of a 15" ThinkPad T61 which is nearly identical, hardware-wise, to the MBP. Initially I kept trying to recreate my OS X workflow in Linux (TextMate with Tranmit, specifically) and had a horrible time of it because the Linux alternatives that are most similar are crap. But once I got over that phase and instead just sought out the best Linux solutions I found that I actually like it better. Now I do most of my coding in Emacs (which is no big leap, it's what I used in college for everything from coding to writing papers with LaTeX), and have created a local development environment that basically duplicates that of the various web servers I'm developing for to simplify things. When I do need to work with remote files I find that gvfs and gedit actually work as well or better than Transmit and TextMate (although TextMate is definitely vastly superior to gedit, and is the biggest sore point in switching to Linux for me, sadly Emacs is for some reason extremely slow when editing remote files via gvfs). I've actually been working on an open source project to extend Emacs to be more like TextMate, and have successfully duplicated most of the functionality I miss most, so hopefully at some point I won't even miss TextMate at all.