As you might have noticed, I referer to Redhat Linux several places on this website. This is not because I dislike or ignore other Linux (or GNU/Linux, if you prefer) distributions, like Debian or SuSE.
I mention RedHat because that is what I use, and have used since I started with RedHat Linux 3.0.3 (Picasso) back in 1996.
When what you use is good enough (excellent, in fact), you may have little incentive to use something related but slightly different (I know I have very little), so today I use RedHat based (Fedora) distributions both at home and at work.
One of the reasons for this is the amount of time I've invested in learning to package software in rpm-packages. Moving to another package system would mean starting over on a steep learning curve.