I have had the 404 for about a week. I am using it in 720p mode and the PQ has been good. Up there with the best of the other upconverting players I have viewed. I demoed the unit side by side with my old Onkyo dvd player and could definitely see the difference.
I have not done anything in the 480i setting as my TV does not like it, so I can't say there. It is a little slow on power up and reading, but I don't think any more than other comparable units. The 404 is pretty small and light. While it doesn't have a lot of "heft", the quality of the electronics is still there.
My only major complaint is with the audio functions. As was noted in the attached post, you need to turn off the audio over HDMI to get Dolby Digital 5.1 out of the coaxial digital output. (Note this unit is also lacking an optical digital output.) As I don't run my AV receiver all the time, this requires going into the menu functions when I do. The other option appears to be to run an additional stereo audio cable to the TV. This is tough for me as the run is long and through the wall with limited room. I also put in the HDMI to have 1 cable that will do it all. I heard other players, such as Oppo, have all the outputs "hot", so I don't know why Onkyo chose to do it this way. As a result, I reluctantly may go another way.