I have evaluated Splunk.

There are several SIEM technologies that are available but one advantage of using RSA NetWitness is that you don't have to outsource the EDR component. It comes as part of the platform. This is in contrast to solutions like IBM QRadar, where you have to outsource the EDR.

In a further comparison with QRadar, it doesn't give accurate results because there are a lot of false positives.

I used other solutions such as EnVision in the past.