Ubuntu rules cloud instances elsewhere? I almost always see the choices as CentOS or RedHat. But that might be my myopic view cause I am always just looking for those right off the bat.
It would be cool to get numbers across all providers, in terms of deployed instances of this or that OS. There's a good story to write, there.
That's were Canonical began to gain traction regarding installs, yet they still can't find a way to get users into support contracts en masse like Red Hat has been able to.
Citation needed. If Amazon Linux is still the default, you're wrong. It is based on CentOS, uses RPMs and yum.
(And I edited my comment since the wording was unclear... sorry if that caused confusion)
Ubuntu has gotten some solid traction in the "web" end of things, while RH is more "infrastructure".