We previously used a different solution. We switched because it did not provide all the things we needed (alert correlation on top of deduplication, machine learning) as well as the ability to easily integrate with multiple monitoring sources.

We use BigPanda now and we will continue to do so, as long as it can deal with machine learning and artificial intelligence predicted by analysis, as it is our main focus. As much as it's a new product in the market, we are also flexible to get any product that we are interested in. 

We did not use a different solution.

Previously, we have used Nagios Check_Mk (aka Multisite) as well as Sensu Uchiwa dashboard to aggregate alerts. With Nagios, were were experiencing scaling issues with the core server platform, given the number of hosts we have in a typical datacenter. Sensu Server solved the scaling issue for us but the monitoring UI for Sensu (Uchiwa) was very difficult to use and had a lot of performance issues. We needed a tool to pull together multiple Sensu instances and provide a workable interface.