transmission and bittorrent-gtk look the best options to me, they seem to follow better the GNOME conventions (just works by default, with the ability to change settings if the user wants to).
The wizard is gone in Monsoon now. So it also 'just works'.
The others look a lot like aMule and similar P2P apps, which just contain too much information by default for the normal user.
What is a normal user? What is too much information? It's hard to quantify. However, a good client should be able to quickly and easily hide excess information. I did a quick screenshot routine of Monsoon showing some of the things which either aren't available in the version that was used in the review or were missed.