I have the Extollo LANPlug 2000 and it has by far the best performance (rock solid pings of about 3ms in my house), but:
1. It works terribly if you use more than 2. There's just some bug in the L2 switching where it will get confused about the destination; broadcast packets get through, but some packets to specific hosts don't go through. Rebooting the adapter fixes it temporarily. I ended up moving one device to WiFi and as a pair it works reliably
2. The firmware it ships with is a bit limited, but they provided me with something more configurable when I contacted support about issue #1
The more advanced firmware they sent me allows tuning what broadcast traffic is allowed through. Note that with either firmware, broadcast traffic worked fine, but it would just seem to get confused about where a specific MAC was.
1. It works terribly if you use more than 2. There's just some bug in the L2 switching where it will get confused about the destination; broadcast packets get through, but some packets to specific hosts don't go through. Rebooting the adapter fixes it temporarily. I ended up moving one device to WiFi and as a pair it works reliably
2. The firmware it ships with is a bit limited, but they provided me with something more configurable when I contacted support about issue #1