My friends and I struggled to find a good router for along time - this included gaming, torrents, and direct downloads. Several wireless devices of various configurations.
Take a look at prices, by now the DIR-655 should be cheaper - we've had ours for over a year now I'm guessing.
Anything but the highest, most brutal usage brings it down. You do need to tune your Vuze settings - if you have more than 1 computer downloading torrents at a atime (try to avoid that...), setting each of their Max Simultaneous Connections to 100 and testing should work. Drop it by 25 if you're still having trouble.
Don't forget, wireless devices cannot send and receive at the same time. The DIR-655 is MIMO (IIRC), so it minimizes the drawbacks, but any individual device can still only send or receive at a time, so torrents are kinda a nightmare for wireless in general.
-Red