There's really no reason to ever use Mesos. We switched over to Kubernetes and it's been a breath of fresh air - better CD support, easy CLI for browsing logs, no mysterious dangling redeploys. If you're looking for a tool to manage a fleet of Docker containers on VMs, Kubernetes beats Mesos by a wide margin.
If you need to automate the deployment of environments in Kubernetes and these environments should be easily replicable in other regions of your cloud provider or even in other cloud providers, then this is the tool for you. Just be prepared for a certain degree of complexity when creating the charts.
Mesos may have many frameworks. If you have Mesos installed on your servers, you may use it for many kinds of tasks. Today we're running only web applications but the idea is to install a different framework for big data soon.
Unreliable deployments that would fail for no good reason. Sometimes our Docker container would be "restarting" forever because Mesos thought it didn't have enough resources to start the container.
Impossibly slow UI. Built in React under the hood with a lot of bloatware backed in, so loading the Mesos UI on a slow internet connection was painful.
No real logging solution - it would stream "console.log()" output to the UI, but searching for logs wasn't really possible without downloading a huge file.
No built-in support for redeploying containers from a CI. We had to create a service whose whole job was to expose an HTTP endpoint that restarted a container, and then made Circle CI ping the endpoint whenever we wanted to redeploy.
We didn't really need support, but the open-source community seemed responsive and informative when it came to issues. Many cloud native consultancy companies (including ourselves) offer support for Helm.
Kubernetes is really great and their community is growing really fast (Google influence). We evaluated it in the beginning and it would fit for our web applications workload. We decided to proceed with Mesos because it has more potential. You may use a different framework for different kinds of tasks on Mesos. There is a Kubernetes framework for Mesos, by the way.
We have a natural trending to use what is a reference in its space and Helm has being leader in its area for a long time. Since it has all features we need didn't make sense to us to invest time on researching and testing other alternatives, so Helm was our first and only tool in regards of automating deployments on Kubernetes
