I have been using Netflix for about 2 years now. I love it. Great price, great service.
If by download service, do you mean the watch the movies in browser feature? If so, I use it all the time. More so at work, or when I am not at home and able to watch a dvd on the tv. It doesn't have the biggest selection but they are continually adding to it. As far as the resolution goes, it is judged on your internet speed. It is played on your internet speed so if it is slow, it will load a crappy quality copy. If you have a decent internet speed, it will give you a nice resolution.
If you meant the TV box set, I have not used it. I am not sure if it is out yet. It could be, though.
Overall, I recommend it.