I think everyone is clear on the fact that after 9 months Kubernetes is not yet as mature as the 4-5 year old Mesos. But people love the project and the direction that it's headed in, to such a degree that there are partnerships forming, startups emerging and many many people contributing to the project. Many of us who will adopt Kubernetes are not looking to scale workloads across a Twitter or Google scale environment. We might have a few hundred machines or less, some might go beyond that but in all honesty I'd say for the time being people can resort to 100 machine clusters and manage multiple clusters.

Don't get me wrong, I really like mesos. I think it's a fantastic piece of technology and I really want to see it do extremely well. I just think Kubernetes is something a little more accessible to the wider developer community. Plus we get to see it grow from infancy and help contribute to that growth. AND its written in Go, which is a major plus.