Saruman's Treachery

[Neithan]

Ultimately, I think Saruman is easily the match of Sauron in his mastery of treachery. His 'term' in Middle Earth has been shorter and so he has not been able to build up the forces to match those of Sauron, but his knowlegde and skill are a good match.

I disagree. Gandalf is said to be equal to Sauron and is greater than Saruman. Saruman did not have to be as great as Sauron to resist a total take over of his mind. Such things are rare and difficult (and probably impossable for one Maia to do to another). Sauron did manage to awaken evil thoughts in Saruman that were already hiding under the surface, but I am sure that Sauron new that Saruman could be treacherous, after all, that is quite common in evil servants. Saruman knew some of Sauron's weaknesses because of the time he spent studying his arts. This does not make him greater than Sauron. Also Saruman could not have invented the rings on his own, he was jealous of Sauron and of Gandalf. Elrond would refer to Saruman as having great power because, as a Maiar, he did have great power when compared to Elves and Men.
Saruman was powerful and skillful (especially with osanwe) but he was not as great as he liked to think he was. His jealousy of those greater than himself ate away at him until he became what he was. Very similar to Morgoth who was jealous of the gifts given to his brethren, thinking himself more worthy than they. Morgoth and Saruman both mocked and immitated those they were jealous of, the diffrence is the scale of their evil.