Graylog's search functionality, alerting functionality, user management, and dashboards are useful. They also provide an easy way to create dashboards, and the interface is also quite easy to use.

We're using the Community edition, but I know that it has really good dashboarding and alerts.

I like the correlation and the alerting. If I have multiple monitoring systems and I alert Graylog, Graylog will collect them and analyze them, and issue one alert.

We are only approximately four months into production and have not explored all of the features this solution offers. So far, it has everything we wanted.