I just purchased one of these off eBay for about $40 to use with my 40Z4100S. The main draw for me was that I would be able to integrate Netflix into my TV's functionality without having to turn on another component. It accomplishes this goal very nicely.
However, it is indeed a clunky piece of equipment. Once the stream starts it's fine, but the interface is very slow and lacks features. I don't understand why the interface is so terribly slow, as it is obviously just a custom web browser for the TV. It should be much lighter on its feet than it is. It obviously has enough processing power to stream in HD, so why is it tripping up over the browser? Sony needs better coders.
Comparing the NV1 to the Netflix disc for the Wii, which I was using before I got the NV1, it has far less capability. I can only view Netflix titles that are already in my instant queue on the NV1, whereas with the Wii I could search genres as well as view the "Movies you'll love" section (or whatever it's called). The Wii beats it hands down on the interface, but of course lacks HD, and using it means I have to boot up the Wii, get out a Wii-mote, start the Netflix app, etc. So even with the slower interface, the NV1 is still a faster way to go.
I'll probably end up replacing the NV1 with a Sony Internet-enabled Blu-Ray player down the road some time, but I'm not too thrilled about having to turn on another component and wait for the Blu-Ray player to boot up in order to start watching my Netflix. I really like how the NV1 integrates into my TV's XMB.
In summary, I had great hopes for the NV1. The concept had great potential, but every time I use it I am woefully reminded of what the device could have been, which is in stark contrast to what it is.
Does anyone know if any of the network Blu-Ray players integrate into the TV's XMB like the BIVL does? I assume that would require a DMEx USB connection, but I would like to be wrong.