We use WhatsUp Gold (WUG) to monitor our servers (physical and virtual), as well as our internal network traffic. It allows us to be proactive about our server and network performance, as well as access perfomance history for capacity planning.
Perfomance metric monitoring. We are able to specify the performance metrics that are important to us on a per-server basis and set custom alerts when the server exceeds those thresholds.
Customization. We were very easily able to design a custom dashboard that shows us the information we need in the way we need it.
Historical data. We can drill down on each aspect of a particular server's performance in a time range to assess its load and if changes are needed. This is especially useful in our virtual environment
Network monitoring. We use the Flow Monitor module which allows us to see in near real time what data is traversing the network and who the responsible parties are. Now when people say the network is "slow" I can pinpoint the root cause quickly.
While it is easy to get up and running, I know I could utilize the software better if I had some formal training on it. There are a wealth of features available, but I don't have time to learn them all in depth.
The training classes offered are very expensive. I'd love it if IPSwitch offered some kind of reasonably priced training options.
It works great in our environment, which is highly centralized and has very few cloud-based systems. In a cloud heavy scenario, I don't think it would perform as well without a great deal of additional configuration.