Both Ian and Tyler were great. It was good to see Ian continue to evolve, at least to me, from a bad guy to a good "bad boy". I also laughed at a lot of Ian's antics.
However, Tyler came in as a new character, and he made quite an impression. While the whole gay thing (What can I say? I'm a guy and it's a little different) was challenging for me at first, But as the story progressed, I liked him more.
I think I have to give the nod to Tyler by a small margin. Bringing in a totally new character can be risky - and this one was a real success! Ian was good, but his part is a expansion of the character already established. Tyler was brand new - totally unknown. He was a surprise - and that gives him the edge in this comparison for me.