Very Happy With GNOME Shell
I use a CentOS7 machine for web development and conducting system administration tasks. I have tried various desktops but GNOME Shell is my favourite by a long distance. I can tweak its looks and behaviour to my liking with minimal effort.
It makes sense to me that Red Hat chooses what they believe to be the best available desktop and focus their efforts on making it work as well as possible. There is nothing to stop people installing alternatives from source as long as they don't expect support from Red Hat.