What are some alternatives?
When comparing NetXMS and Zabbix, you can also consider the following products
System Center Operations Manager - System Center Operations Manager 2012 R2 uniquely enables customers to reduce the cost of data...
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Opsview Atom - Monitor everything. Integrate anything. Scale anywhere.
LogicMonitor - LogicMonitor is the SaaS performance monitoring platform for the world's best IT teams. Deploy Fast, Monitor More, Improve Ops.
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
OpenNMS - Project home page of OpenNMS - a java based network managememnt platform developed under the Open Source model