The old 360 dashboard wasn't sharp when displayed in 1080p and the new dashboard isn't any better. However when displaying games or movies, the 360 and PS3 are equally sharp all other things being equal (obviously not in games with different rendering resolutions on each console). The biggest difference I see between the 2 consoles in the clear difference in gamma each one has. 360 games tend to be much darker then the same game on the PS3 after calibration.
6/23/09 at 8:31pm