Azureus vs Transmission

I understand the difference of features between different OS X Bittorrent clients, but I have a different question. Which Bittorrent client is the most lightweight. I'm just wondering which one is quickest/uses the least RAM/CPU. Is it Azureus 2.5, 3 or Transmission?

I've tried other torrent clients, but I personally find I get better speeds in these clients.

Azureus is a giant resource hog. Transmission is a much lighter client. I'd recommend either Transmission or Xtorrent (which I use).

OK, what exactly are torrents? I've seen it mentioned around the forums. Thanks for the info...

Thanks for the link... so, I now have to pose the question- why bittorrents? It seems to me that the only feasible reason is to save someone else money? Perhaps I didn't understand it completely- look forward to learning more.