I see several people claiming that if Nintendo "wins", the hardware race will slow down? I don't see any reason that this opinion is justified. Nintendo's been on both sides of the coin, the higher powered side as well as the lower powered side throughout their console history. There's nothing that says if Nintendo gains market share this time around everyone will stop increasing horsepower and just sit idle. Anything can (and will) change in 4-5 years time. I realize that the wii didn't follow the same direction in massive power increases that the other two did, but I think it's clear that they did it on purpose (either to differentiate themselves or because they spent the development money elsewhere so settled on a moderate power increase to keep costs down).
To keep on topic, I would predict very little difference in pro/con no matter who wins this iteration. The hardware is only a minor player on the evolution of video games, the main driver in this industry has always been the creative minds behind the games.
Though, if the wii becomes a stellar hit, I'd assume motion sensitivity in games would be taken much more seriously than it has in the past =).
