Weren't previous PoE hats just ethernet splitters that also had a 5V output to the Pi rails, but still required another Ethernet cable to connect to the Pi's actual Ethernet port?
This is definitely not PoE, just a hack on top of normal ethernet infrastructure. If you use one of these with a normal PoE switch you will fry whatever is connected on the other side, as it won't step down the voltage from 48V to 5V. Both sides need to be using this, but then real PoE is guaranteed to work even on 100m long cables, with this your 5V will end up being <4V with a 100m long cable and potentially useless.
Nope, this is not the ghetto "Passive PoE" variety which uses the 4 wires not needed for 100Mbps to carry power. This is an actual 802.3af/at compliant adapter.
I have 2 in my home (not the exact model I listed because I'm on the other side of the Atlantic, bought them off Amazon Germany), hooked to a Netgear GS110TP (8 PoE copper ports, 2 SFP ).
Actually there's so much stuff drawing power (2 Pi, 2 Ubiquity APs) that I'm starting to worry about the load on the switch.
Let's see how much the official PoE HAT is, but it better be cheap or I know what I'll be buying (more of)