Don't know, theres too much... but favourites are:
* That we are totally in control of our application server in Realtime
* What the guys of FusionReactor did add to their products in recent years is absolutely awesome. 5 years ago, we thought we have all we need - and what we get now in the newest version is simply mind-blowing
* The guys of FusionReactor are there for you, high competence in support and very effective sales
Sitting here and thinking... honestly, I'm missing absolutely nothing and no feature at the moment.
Take the time to read the docs and to "play around with this tool - not just jump on the first figures and lists you see. It's really worth to understand and see all the options and possibilities FusionReactor offers.
We are not having internal tec guys, but external DevOps team. With FusionReactor we have the tool in our hands to react before any monitoring would report an outage. We share access to the tool with most developers and get the hints and tips, what to work on first, and what queries or transaction are a threat for the future.