I really prefer DC/OS to K8s. They both have strengths and weaknesses, but I hate we're not this k8s monoculture now. There need to be more container orchestration systems .. and don't kid yourself; few shops are using nomad.
That's probably about it. Right now, I'm jumping on the k8s bandwagon, but looking to keep it simple. As much as I'd like to look at nomad seriously, too many times I've been caught by not looking at the mainstream.