For instance if you go to Mono's download page to checkout the options, the only Linux distribution supported by them is OpenSuse: http://www.go-mono.com/mono-downloads/download.html
Of course one could argue that Debian (and Ubuntu that relies on Debian's repository) has a culture of packaging stuff by themselves and indeed in the case of Mono there are people that do just that. But those packages are always behind the current version and you can't blame the maintainers for that. And lots of software companies, including Google and Mozilla, are providing packages for Debian/Ubuntu for the latest versions by themselves. It's actually the norm with Ubuntu to setup third-party PPAs that provide packages for something missing from the main repository.
So Miguel here complains about fragmentation on the Linux desktop. It's funny, because they ignore the largest distributions around. At least if instead of OpenSuse they supported Red Hat, I would understand.
Also, my experience with OS X has not be so pleasant. Miguel is a damn good developer, but he must be using a really simple toolchain.
When you are working day-in day-out with Java, Ruby, Python, Javascript, Mysql, Postgresql, GCC, Casandra, MongoDB, Memcached and dozens of other technologies, installing that stuff and having it work on OS X is amongst the most frustrating experiences I ever had, no matter if you're doing it by hand or with MacPorts or with Homebrew. All available options on OS X suck. I couldn't give a fuck about binaries of commercial software packages working, as long as I can't manage the toolchain I depend on daily.
Another thing with OS X is that it just works, until it doesn't. After that you're in Windows-land again, the preferred option being to just reset/reinstall everything. Linux can be painful sometimes, but for most problems you can find documented fixes.
Also, he's a little out of date. Ubuntu has been rock solid for me on my Thinkpad for the last couple of months since I got my current laptop. Of course, I preferred a model with Intel HD 4000 instead of a Geforce, so a little research into hardware may be needed to ensure good compatibility, but on the other hand you can't run OS X on anything else other than a couple of Macbook models. Try building a Hackintosh sometimes and your appreciation for Linux will change.