I am about to get up and running with mautic for a self hosted marketing solution. Here are some of the reasons I love mautic:
It’s a free self hosted open source software (Just like ClassicPress )
You can host unlimited number of subscribers (bye to limited email contacts)
Fun implementating it your self from scratch.
If you are using mautic or any other similar software, what are the things I should look out for, like best practices for using it securely, and any other stuff I am not aware of.
I have used Mautic in the past, and CP was originally set up using Mautic. I have since moved to paid solutions because I always felt like Mautic was cobbled together (just a personal opinion).
If you are looking for an email newsletter solution I would consider MailCoach, it is also self hosted.