I've been a Linux-on-the-desktop user since 1998 or so, and started using it full-time in 2001. Having grown up on closed & proprietary operating systems with "black box" operation, I found it amazing how transparent everything in the UNIX world was, and how much control you had over your machine.
Lately, I've just been happy that my laptop hardware finally works "out of the box" and with minimal tweaking, so I can get on with my life and focus on the things that matter (I'm a software engineer, so get on to coding & designing software).
I fear that simple usability and hardware frustrations caused many people who would have been Linux/BSD users over to Mac OS X -- a proprietary & closed system that at least has BSD roots. Linux may not be the best kernel design ever, but it's a Free operating system with serious UNIX roots and astoundingly good hardware & software support.
In my current work as an engineer of large-scale web applications and distributed services, I find that kernels and base operating system layouts are playing decreasingly important roles. We are automating these details with tools like Puppet and Chef. We are spinning up Linux machines in virtualized providers like Rackspace Cloud and Amazon Web Service. We want to forget about these details and get on with our lives.
We just need something that runs on our physical or virtual hardware and runs our stack of open source databases, programming languages, and services. We need something that just works.
I only came across one place, recently, where operating system choice seemed to matter -- and that was in the deployment of a pair of physical network router boxes in a colocation facility. For that, we chose OpenBSD over Linux due to its out-of-box better support for high-availability networking, packet filtering, load balancing, etc. But I can't think of another time -- desktop or server -- in the last 5 years where it has made sense to choose BSD over Linux.