Could you check if there is a "Test Network" option in the settings menu like the old Apple TV? It would probably be under Network, if it exists. Netflix's help page says to use it for troubleshooting, but the pre-release build I have doesn't seem to offer the option anywhere.
(If you do find it, what kind of results does it return? like DL/UL speed?)
(If you do find it, what kind of results does it return? like DL/UL speed?)