Equally, I just prefer Debian. I don't like the Ubuntu way, I like having a system which I can easily understand the inner workings. To that extent I've probably just used Debian more than Ubuntu. 

Servers I use Debian Stable

Desktops I use Linux Mint Debian Edition

Before I used Debian I used Gentoo for many years. But once I entered the real world I no longer had the time to keep a system updated and moved to Debian which was the most used distro among my friends.

The rule of thumb is:

Use what you're comfortable with. Failing that, use what your friends/peers are comfortable with. At least then you can get support easily.