What are benefits or downsides in using Swarm / Kubernetes / Mesos / Cattle

As far as branding is concerned the whole thing is just Rancher now and there’s nothing actually called Cattle. But 2.0 provides the same user experience (UI, CLI, compose files) as Cattle in 1.6 (give or take, plus many improvements). Instead of reinventing the same wheels as a separate orchestration system, it’s just provided on top of Kubernetes now.