When was the last time you used PRTG? Just in the last year they have made leaps and bounds. PRTG has truly matured to compete with bigger more expensive solutions.
I worked at a manufacturing company several years ago that had 14 site world wide. They used SWI and then was introduced to PRTG. In days the IT Director tossed SWI in favor of PRTG. I still know several people who work there and about two month ago they hit just over 8 million sensors (element in SWI). They monitor literally everything that is connected to their network, including the assembly line and not just the OS that runs them but the custom peripherals that are attached to them.