What are the pros and cons of using a powerline net adapter, such as latency, speed, line interference vs a good late generation wifi card vs. direct Ethernet to cable modem?
Depends on your wiring, distance, and luck.
I had good luck with them. You can run a bunch in the house and they'll all talk to each other. If you run a lot run off a modem/router, the base can get pretty warm.
-Occasional reboots were needed more than either wifi or direct wire.
-they're not perfect. Direct wire is better. Wifi is adequate if the distance is short. If you're just trying to get one pc that's just out of reach of your wifi router, powerline adapters shine.
-I had a friend that complained about noise on his guitar amp when they were in use.
Better off with MOCA v2 adapters if you have coax running to each location. Though you will need to put in a filter and for best performance perhaps replace splitters.