Okay, first of all, "his" rendition of Ring of Fire was not his rendition. He did not arrange it, Jeff Buckley did.
If he got up there and sang Garth Brooks or Brad Paisley he would have looked and sounded ridiculous. Kudos to him for not pretending to be someone he is not.
I personally liked it. He is a breath of fresh air amongst a bunch of clones (with the exception of a few, of course.)
"You see, I told you so! There's lots of things I know. 'Ponine, she knows her way around."