vRealize Operations for Horizon is available as part of Horizon Enterprise or as a separate product. Where vRealize Operations differs from most monitoring tools is in its analytics engine. Most monitoring tools are based around setting thresholds for key values, such as CPU, or memory consumed. The issue with these kinds of alarms is that simply stumbling over a threshold value doesn't mean there is necessarily an issue. Sometimes, it is within the normal parameters of the applications in use, or potentially, the problem could be one of the resources not being consumed when it should be.
With the analytics engine included within vRealize Operations, it is able to learn and understand what the normal working parameters of your environment are. From this, it is then able to alert you when an error occurs that falls outside these parameters....