The hosting aspect of the game will be the same across the platforms I'd've thought. When the game launches the host becomes the parent and all other players become the children. The parent is responsible for collecting all network data from all the children then redistributing the entire data set back to all the children. So lagginess is determined mainly by your ping to the host.
It's a pretty standard network model. CoD uses it too. That's why everyone gets dumped when the host quits, unless some sort of host migration feature is implemented which will find a new (and hopefully best) parent from the children.
Dunno about the leaderboards though - I don't think ours have been reset...? Although the upside is, if we're getting bigger scores now, active players should rise up faster than existing inactive players.
Sorry if the first word of your post was an attempt to stop me replying, but the answer is fairly general and non-platform specific
