Yes I have seen. I am a Fan of the Fire Ep. When she had you use 2 cards to catch it, and the song was something i could never forget.
Not only that. The last Ep with Yui. XD I fell in love with him as a little girl.
Took me a while to see the First Ep.
As for my favorite. Yui because he's 2 faced and that can always be hot.