Not exactly the comparison you're looking for, but Netflix on my Panasonic BR player and my ATV2 both have pretty good PQ. The interface on the ATV2 is MUCH better, but the PQ I think is the same.
The better comparison will be on Monday (October 18th) when Sony begins offering Netflix streaming to the PS3 at 1080p and 5.1 DD Surround Sound. I agree that the current version is bad.
If you are a pixel counter, then the PS3 on monday will be your best bet. If you are just an average Joe looking for good quality, the ATV2 is good enough that most people can't tell.