Data center infrastructure monitoring is not a one-size-fits-all proposition. There are many parameters you could monitor: power, energy, temperature, humidity, pressure, etc. There are also multiple levels in physical and organizational hierarchy that monitoring could be deployed at: main feeds, PDUs, cabinets, busways, servers, etc. Obviously, you want a system that supports as many parameters as possible and covers them throughout the hierarchy.
What is sometimes forgotten, however, is the dimension of time. Good monitoring also takes place on multiple time scales.