Snow Leopard recognizes the device immediately. But even though it seems to be able to handle the presence of the device, it won't recognize an active Ethernet cable is connected. Only after repeated reboots with various attempts did the device finally work as required.
Otherwise, it seems to get the job done, albeit in a somewhat overpriced fashion. It works just fine with a 2-meter USB extension cable between it and a MacBook Air.
I purchased this product for an end-user who purchased a MacBook Air (has no ethernet adapter onboard)... First thought was to use wired internet to download all updates/applications, however was disappointed - download speed was 60 kbps (have had download speeds up to 10 mbps on connection), so switched to wireless, which gave 1.0 mbps on same download. Wireless is much faster then ethernet can handle with this adapter. Only way I see this adapter worth while is if wireless is completely unavailable on your network...
