My predecessor at my current company used a platform called check_mk to monitor our network.  Unfortunately, check_mk has a feature that populates based on network discovery and can be very chatty. check_mk is also very convoluted as it’s built on top of Icinga, which is built on top of Nagios.  When making changes, there were layers and layers of configuration files you had to dig through, at least, in the check_mk instance my predecessor had bequeathed me.  Needless to say, I was not a fan and it wasn’t very efficient.  I understand why they forked to create Icinga.  At the time, Nagios was stagnant.  Since then, I feel like the Nagios camp has progressed significantly.  I also understand why they forked Icinga to check_mk, but it’s not for me.   For the granularity I want in monitoring, check_mk would be more work intensive than Nagios.