Speaking for myself, I chose Linux over BSD as main OS back in the day (~1998), even though BSD was "hot" in hacker circles, because Linux had a slight edge in convenience. Configuration of X and such were slightly easier with Linux (Slackware back then), and HW support was somewhat better (though FreeBSD came close).
Also Linux has the GNU utilities (GNU grep etc), which were somewhat more featureful than the BSD equivalents. I know they can be installed on *BSD though the ports system but as I was new to unixy OSes, having a lot of packages installed by default was great.
I have no idea how it is these days, Linux just stuck.
I too started with a linux in the late 90's but moved to Free/OpenBSD by 2000 as IMO the BSD community had got it's shit together and the Linux community had turned in to a shambles optimised by slashdot style commenting everywhere.
By that point the BSDs supported most common hardware and didn't suffer from fire and forget IDE drivers which corrupted my Linux servers at least once per year. Although they were slower they just seemed to work. Combine that with a rational layout of /etc /usr/local/etc and all the other places that UNIX's squirrel away files and BSD just stuck for me. I haven't looked back as far as servers go.
The desktop is another kettle of fish though. Ubuntu is still far better than PCBSD but both are still lightyears away from the polish that windows/mac desktops have.
I chose (Free)BSD over Linux back in the day (~1999) also for reasons related to X. The Linux distributions I tried came with an X server that didn't support my graphics card (a Voodoo 3 3000!). FreeBSD got the latest X server in the ports and it ran fine on this card. I later moved to Linux (Debian then Arch) but FreeBSD was a great learning experience, and it felt clearner/more organized.
Also Linux has the GNU utilities (GNU grep etc), which were somewhat more featureful than the BSD equivalents. I know they can be installed on *BSD though the ports system but as I was new to unixy OSes, having a lot of packages installed by default was great.
I have no idea how it is these days, Linux just stuck.