Right now, I don't like him. I do think Paul is Ash's perfect rival. But I don't think Ash needs to be slapped around. Maybe people have forgotten, but the show isn't the same as the game.
Paul represents the competitive pokemon gamers that EV and IV train their pokemon, with perfect natures, characteristics, moves, types, and stats. Think about it. When you EV train a pokemon and looking for a specific type, you release all the ones that have the wrong nature; just like Paul does when he catches one that isn't strong enough to him. But in the show, pokemon aren't raised by equations and variables like they are in the game, they're raised like living things.
And Ash represents the normal gamer, one who catches a pokemon, and raises it as is. Which is the majority of people who play pokemon games. And is what the majority of people in the show do. And the characters in the show are cheesey, but Pokemon is aimed at little kids, so it's cheesey to us older kids, but not to younger ones.
But I think Paul has potential to be a likeable person in the show. But at the moment, I don't like him that much.