could be used in conjunction with a pdu, I use a metered pdu but sometimes I do wish I knew individual stats as far as wattage/power measurement for my rigs
The interesting thing here is when you're building out something, there's really no need to use a PDU at all - you could just wire up your own with a couple of these in series from the feeder power source, just make sure to pay attention to wire gauge, etc. Assuming you were doing 208-240v 30a breakers, you could easily do a couple of these per and have individual monitoring/control.
After a bit of research, there is a product that seems better from this manufacturer the Sonoff S20 is a real plug that can be monitored and remote controlled, thanks to alternative firmwares like https://github.com/arendst/Sonoff-Tasmota, it's also compatible with the Sonoff Pow. I like the idea because it's 1/3 of the price of the TP-link i use. Will try to source some and play a bit 
The S20 doesn't have power monitoring, just power control - plus the plug isn't really the kind you'd use for larger rigs, just for things running on normal outlets.
I'm torn about using a Cat-5 version or not - since this is per plug, the cost of switches and all the wiring nightmare it would cause with larger installs would be a bit of a PIA. I made my own Temperature/Humidity monitor with the ESP8266 a year or so ago, and it's surprisingly stable and reliable for being such a cheap component.
