Meh, I didn't like Cena much even when he was a heel. Too much of the same thing all the time. Stupid rhyming promo, with the obligatory gay/dick references. The only difference between then and now, is he plays to the crowd more, and wears the hometowns' jerseys.
He's done good, for such a limited gimmick, however. Shame his ringwork hasn't really improved.