First, let me be clear - it was Jamie's mentoring that I was pleasantly surprised by. Not his so-called performance! Anyone who has seen "Ray" knows that Jamie has a good voice. Or maybe he's a good mimic. But I doubt he sold many records after elimination night last year!
I tried to find some recaps to help me remember what impressed me about Jamie. It seems that he was a bit unconventional and had interesting observations. He got up in Gokey's "grill" to help him break down a wall. He suggested to Allison that she think of her family for "Someone to Watch Over Me" because she was too young to think of a man/boyfriend in the way that the song projected. He said he would like to record with Kris. He seemed to be amused that Adam didn't care who he was, meaning that Adam had a lot of confidence in himself and Jamie didn't "wow" him. I don't remember and couldn't find any interaction with Matt. I think it was somewhat glossed over.