Miz is the more entertaining and charismatic character, and he's one of the best promo guys on the roster, but his matches? Eh, the vast majority of his matches are very underwhelming and dull. On the other hand, Cesaro is the better in-ring performer, easily, and he has a handful of five star worthy matches to his name over the years. Although, Cesaro's new James Bond style character (and the entrance) is not the right fit for him, and I have trouble believing he'll be able to pull it off with more time in the coming weeks and months.
Cesaro needs this more than Miz. A loss in a title match will kill whatever momentum he has, but WWE constantly mishandles Cesaro's feuds and storylines, and pairing him with Heyman after Wrestlemania XXX was a colossal mistake, so I have no reason to believe things will change here. Miz retains, because you have to believe WWE really wants to push Miz and Maryse as another power couple.