From the perspective of a provider and looking at what my customers are currently using, very few actually utilize Ubuntu these days. Some do because of some game control panels function better on it as they were developed for it primarily, however in the web hosting world the most popular operating system these days is CentOS.
I'd personally say no, only because I've actually never had to use it. I'm kinda a huge fan/user of CentOS 5/6. But people use linux for different uses, CentOS is for more enterprise use, like hosting!
Ubuntu is used by 26.1% of all Linux websites, behind only Debian (on which Ubuntu is based), which is used by 32.7% of all Linux websites. Ubuntu is the most popular Linux distribution among the top 1000 sites and gains around 500 of the top 10 million websites per day. Source: WiKi
However, Ubuntu is the fastest way to build an OpenStack cloud. its comes with complete package included cache repository etc. not like CentOS.
Now a days 40% of the datacenters using Ubuntu in short time. Pretty good!
Ubuntu Advantage is the professional support package from the experts at Canonical, helping organisations around the world to manage their Ubuntu deployments. It includes access to Landscape, the systems management tool for using Ubuntu at scale, as well as 24/7 telephone support and the option of a dedicated Canonical support engineer on your premises. Ubuntu Advantage subscription tiers are based on the size of your deployment and the support you need. and CentOS? humm.
Generally Ubuntu is used for the Desktop environments and its the best options for the machines instead of windows os as its free but centos is most preferable OS for the dedicated server environments.
Ubuntu is based on the venerable Debian distribution. CentOS is a free clone of Red Hat Enterprise Linux. The respective origins of each distribution shape the most important difference from a userâ€™s perspective: the package management system.
All my 5 VPS run on Ubuntu 14.04. I use them for wordpress sites on nginx with php-fpm. Moved to Ubuntu 2 years ago and I do not regret my decision. The community is big and it's easy to find answers to most questions.