Mackerel is a very simple tool to use. It's easy to set up, easy to use, and has a lot of features. It's very easy to get started with and the documentation is very good. I've used it for a few years now and have been very pleased with the tool. It's not the cheapest tool out there, but it's worth it. I would say that the support is very good. I've never had to wait more than a few hours for an answer and the support team is very responsive. I've used Mackerel for monitoring my servers. It's been very useful. I'm able to monitor the servers and keep an eye on the performance of the machines.