I don't consider the Popbox UI anything spectacular. For all the hype it's really no big deal. I am not interested in thumbnail depictions and IMDB data. From what I have seen of the Fusion HD UI from the YouTube videos it is totally satisfactory to me. As far as Netflix...I would gladly forfeit a Netflix for a box that gets the job done in the area of it's core function and that is playing multiple media formats (video, audio, photo). I would like some internet content capability. That's what makes the Boxee Box so appealing but we don't know yet if that product will perform as advertised.
This is what I've learned with the negative Popbox experience, the product is only as good as the company behind it