How good are heartbeat, elasticsearch and kibana as a monitoring/alerting solution as a replacement for Nagios? Since we already have filebeat, metricbeat and heartbeat configured and running.

I wonder if people have successfully implemented the ELK stack for actual monitoring with alerting/notifications instead of using traditional software as


Nagios
Icinga
Zabbix


Especially since ElasticSearch now has had watchers and alerting for a while.
I haven't tried it myself, but in Alarms management with Elasticsearch and Kibana someone recommended Elastalert