This page shows “mathematical analysis”:http://konspire.sourceforge.net/BitTorrent.shtml of file distribution with BitTorrent, and comparing it to another system called konspire2b. The assumption is a bit biased towards konspire2b, but it is a good read nonetheless.
Morale of the story: The more chunks a file is split into, the faster you are going to get it with BitTorrent. (but the torrent file gets bigger)
I just realized I felt a bit high reading this article. I must be a dork.