For every five seconds you spend cleaning your DS screen, you'd probably spend a couple of minutes watching loading screens on the PSP. (sorry, couldn't resist).
Viewtiful Joe on DS makes me happy! I'm surprised at how much support Capcom is giving this series - I didn't think it was that popular. The first did well, but not that well, and the second game bombed...still, I can't complain because I'm very interested in this game.