I work at Volvo Car Corporation as a consultant Project Manager. We have deployed Zabbix in all of our factories for factory monitoring because after thorough investigation we saw that Zabbix supports the wide variety of Operating Systems, hardware peripherals and devices a Car Manufacturer has.
No other tool had the same amount of support onboard for our production environment and we didn't want to end up using a different tool again for several areas. That is the major strong point about Zabbix and it's free of course. Another strong point is the documentation which is widely available; Zabbix Youtube channel with tutorial video's, Zabbix share which holds free templates, the Zabbix online documentation and the Zabbix forum also helped us out quite a bit. Deployment is quite easy since it uses templates, so almost all configuration can be done on server side.
To conclude, we are really pleased with the tool so far, it helped us detect several causes of issues that were a pain to solve in the past.