i work for one of the top ten Fortune 500 companies in the US. We have more linux servers than i have ever cared to count, but should near the 4 digit range. However, the majority of them are RHEL/CentOS, with some SuSE, Ubuntu, and even Fedora mixed in. We have 2 main issues using Fedora in the enterprise, one being the short lifespan, second being the untested nature. The people utilizing the services on the servers dont want to take risk, and also dont want to replace it every year. They just want it to work, and keep on working. Developers on the other hand, want the latest and greatest. But also dont want to do any upkeep, thats Ops' job. Ops doesnt have the time to constantly be upgrading servers. The new modularity initiative could help to make both devs and Ops happier, but it doesnt make the users happier.
However, we are trying to make pushes towards a continues delivery system for many things, with OpenShift and Mesos mostly. In my opinion, this is where fedora has the chance to get in further use. But not as the "server" platform, but in it's Atomic form. We would have no issues at all rolling atomic hosts in and out of clusters all day long, mixing Fedora versions. CentOS/RHEL/Fedora, it doesnt matter, because either way that atomic host will be replaced next month anyways. In some ways with large environments its easier to just deploy newer atomic images on rotation than it is to do ostree updates to them all.
At home I just switched to Fedora atomic from CentOS, and run all of my home services in persistent containers (I know, but i want them persistent, i still do dnf updates!). The usual Nextcloud, postfix/dovecot, minidlna, unbound DNS, OpenVPN, etc, etc.