Brultech ECM1240

Uses an AC to AC converter to pick up phase offset between current and voltage and compute PF.
120 and 240V compatible.
Can sample 7 currents, 2 of which directional (allows for solar panels and other generation).
Lots of CTs (current transducers) to chose from.
Serial, ethernet, or Zigbee (wireless) interface.
Cheap (starts around $200). Cheapest entire granular house monitoring option I found.
Needs windows to configure, but platform independent python code to query the data (up to once a second).

Uses an AC to AC converter to pick up phase offset between current and voltage and compute PF.