I know it's young still, but I think Nomad is going to get a share of this market with little effort.
I played with Mesos & k8s and I picked Nomad instead. Now I'm not managing a huge fleet of servers I want to abstract away as much as I wanted a simple, consistent framework for allocating resources to containerized tasks across a small group of nodes. And I don't think that use case is anything to sneeze at and for a new user there just isn't anything out there as easy as nomad IMO.