Alliance’s user interface is very intuitive and easy to use. You can search for files in your private network and browse through your friends files to see whatever they have to offer.
Like BitTorrent, the application supports multi-source which means that the transfer speed will increase when more people share the same file.
Another great feature is that you link directly to files in your Alliance network when you are chatting with friends, which makes sharing files even more easy. For all files on the network you will see a download speed indication, the more people share the file, the faster it will be of course.
The latest version of Alliance (0.9.8) is designed to share files securely and uses a very simplistic encryption algorithm, but there is experimental support for more advanced algorithms.
Personally I think that the application has much potential. It could become very popular on University campuses for example ;)