i don't really know why people expect him to be awful. he's charismatic and more geared towards comedy than seriousness. so he's pretty much at the same level of most other first time hosts.
this will be one of those "wow he did so much better than i ever expected" weeks, or "i didn't like him til he hosted snl" weeks. musicians as hosts are usually really good. it's the athletes and politicians who usually suck.
but as often as justin timberlake is on, i wish they'd make him a regular
i think he'll do a good job on snl tho since comedy is more his thing