They are pretty much the same. The download speed is mostly given by your Internet connection and the quality of the server that hosts the file, so the application that you use doesn't really matter that much. However, as far as stability and overall usability go, BitTorent is a lot better.
In case you're looking for an alternative to BitTorrent, I recommend trying out ForstWire. The tool has some very interesting additional features that you might like.
