Every company I've been at, they haven't cared. Most people ran Red Hat just because it's what IT gave them, but as long as you could get things done, no one bothered to ask "which Linux" you were running.
On the other hand, I do have to run a kernel with hundreds of Red Hat patches applied, because ClearCase (the RCS system at Brocade) requires a kernel module that won't load if you're not using a Red Hat kernel. So I run debian with that kernel underneath.
On the FC side of things, we've got about a half-dozen workstations at ibiblio running FC2 with no appreciable problems. There's a little wonkiness on an FC1->FC2 upgrade with the SELinux bits; you just have to do a little voodoo to bring your system into line with what SE expects to have there, and 'su' works again.
Most of them are network installs, which are really fast for some reason, heh.
Oh, and yum is no apt. I have been thoroughly underimpressed.