What are some alternatives?
When comparing MLDonkey and Halite, you can also consider the following products
eMule - eMule is a free peer-to-peer file sharing application for Microsoft Windows.
Transmission - Transmission has the features you expect in a BitTorrent client: encryption, a web-based interface...
aMule - aMule - the all-platform P2P client!
qBittorrent - Lightweight and open source torrent client that runs on all major platforms.
Soulseek - Soulseek® is a unique ad-free, spyware free, and just plain free file sharing application.
Tixati - Tixati is a peer-to-peer file sharing program that uses the popular BitTorrent protocol.