[tremad]

As someone who's configured and worked with almost all of the tools in this list, I can only disagree with you. The old saying of you get what you pay for is some what relevant. But the integration of the newer OSS monitoring tools is becoming increasingly awesome. Take The graphite/prometheus/elasticstack integration with grafana for instance.

I think having one pane of glass to do all passive monitoring tasks is an incredible step forward.

I am yet to see if the Active monitoring of Grafana is any good, but it does look very promising