It’s too early to predict the race, but there is a rule of thumb that is often applicable; voters in a presidential election prefer the candidate with the shorter last name. This rule of thumb may be affected by the state of the economy, but has worked well in many elections. Bush (four letters) versus Gore (four letters) was a virtual tie. Bush (4) defeated Kerry (5). Obama (5) defeated both McCain (6) and Romney (6).
In 2016, Clinton (7) will defeat Christie (8) if nominated. Former Senator Scott Brown (5) would do well against Clinton (7) if he enters the race and manages to secure the nomination. Cruz (4), Paul (4) and Rubio (5) might do well, but none of them will be nominated.