@thatpinguino: It is certainly true that they are both good writers (though their tastes are both far enough off mainstream that I rarely take their recommendations) but there are no shortage of good writers on TV or movies. Go to Rotten Tomatoes for a given flick and you'll find a half dozen other writers who express their opinions as well as Morris does. I think the editorialists benefit far more from being on Grantland than Grantland benefits from having them, though without the site traffic this is all just one man's opinion obviously.
I'm sure that the expanded audience the Grantland affords is super valuable, but I think that having quality writers has raised the site's profile. There is a nice synergy there that allows writers to ply their craft and expand their audience and it allows the site to hold its position as a premiere spot to read strong sports analysis and cultural criticism. I think a lot of the writers were given a big platform and a break by Bill Simmons and the original staff and they validated his decisions by putting out great content.
Its worth mentioning that Grantland employs a bunch of freelancers every week and they frequently have some of the stranger and more interesting articles (the article on the history of the merkin jumps to mind).