I think this was a brilliant episode- it was such a clever idea to have a patient who mimics everyone around him- it was an ingenious way to know more about the candidates! Kutner seems to like new experiences, Taub seems to be into Amber or affairs from his wife, Brendan misses adventures, Amber feels the need to always be right, whilst 13 seems scared about something- assentuating her mysteriously withdrawn character.
I thought it was a good way to go with the characters and to let the audience care about them more. Meanwhile, Foreman returns to the team, much to House's initial displeasure. I was thrilled to see Foreman back, and for him to finally learn how happy he is to be there! He, like House said, was the only one to learn something from the patient. I loved how Cameron told him the same as well, as well as Chase winning all the bets by striking a deal with House- I would have loved to see more of him in the episode, however.
I think it was also interesting how Wilson has more power than House, whilst House has more power than Cuddy- it gave more depth to there relationship. I loved the scene at the end where House and Cuddy competed!
Overall, I thought this was a great episode, with great character development for a cast currently so large, whilst the mystery was also very interesting- a House classic.