Zabbix is a bit opaque to tune and the support forums aren't super helpful unlike say Nagios. That said it does some really cool stuff like tree walking across

Zabbix is a bit opaque to tune and the support forums aren't super helpful unlike say Nagios. That said it does some really cool stuff like tree walking across all the HP switches on our network, auto monitoring all ports it finds and then reporting on their stats and on any UP/DOWN states for every port. Good for detecting unauthorized usage or a device which is rebooting itself. Its IPMI support is also pretty good, we had it monitoring Supermicro IPMI interfaces with zero issue. It handles vSphere and auto scans the entire cluster, adding all guests and monitoring them without needing to install an agent on every VM. All in all a very good solution with some very cool features, but a steep learning curve and not much help on their forums although the docs are pretty good.