What do you like best?
Before Zabbix, I was using Nagios as the monitoring system, Munin for usage graphs, and Diamond for application specific graphs. Now, we are able to keep it in one, slack solution, which is easier for developers to use. There is a great community, which is very helpful, and on the GitHub, you are able to found a lot of templates for almost any application. Community support is quick and responsive. Using API, you are able to integrate Zabbix with many other applications.
What is important for us - Zabbix is open source software, so we were able to fix some stuff by ourselves.
What do you dislike?
It's sometimes hard to configure, needs strong technical skills. Also, database usage isn't optimal, and there is no easy option to undo your changes if you (for example) remove a host from the zabbix. The user interface could be improved because it's a little outdated. The graphs could also be improved, the current solutions is useful, but definitely, interactive graphs could help with analyzing data.
Recommendations to others considering the product
Sometimes it's better to hire external consultant to fully setup zabbix.
What business problems are you solving with the product? What benefits have you realized?
We were able to cut time, that developer needed to analyze part of the problem, because all graphs, automated issue reporting, and notifications were consolidated in one place. Our alerts are fully automated, forwarded to slack, then if nobody responds in few minutes, automatically send to mobiles of our team.