FriendFeed Rooms Vs StumbleUpon Vs del.icio.us?

Who do you think will come out on top? Does FriendFeed have a better community than del.icio.us? Does the rating of sites (StumbleUpon) supersede simply just commenting about a site (FriendFeed)? Which has the best integration within applications both online and off? Or does this change nothing as each serves its own purpose?