Sam Wang has a great article that looks at the main match-up problem Bush has against Clinton, favorably rating.
The bottom line, in two sentences: 1) Hillary Clinton has Presidential-level name recognition, which nearly the entire GOP field would kill for. 2) Jeb Bush is starting off as damaged goods, but most other Republicans are not.
Hillary Clinton is not only making history by likely being the first female presidential nominee of one of the two major political parties, she is almost making history for being the first non-incumbent presidential nominee with this high name recognition, this is something we have never seen since the start of modern public opinion polling. Jeb Bush, while better known than all the other GOP candidate, is not very popular. This is the dilemma for the Republican Party, do you want the guy that is well-known but unliked or do you take a chance with someone unknown to the majority of Americans and hope his approval rating among the public doesn’t fall once voters get to know the candidate?
Here are three major features I see in the data set.
Hillary Clinton has massive name recognition. She is as well-known as a sitting President.
As of today, Hillary Clinton’s favorability is 13 to 22 points higher than every Republican in the race.
The best-known Republican, Jeb Bush, matches Hillary Clinton’s unfavorability, but lags her in favorability by 15 points. To match her net favorable-minus-unfavorable number, he would have to win over people who don’t have an opinion by a ratio of 1.7 to 1. That is a huge challenge.
When you look at the last chart you can clearly see the real serious problem the Republican Party is going to have to fix before Election Day 2016, the three most favorable politicans on this list are all Democrats. Americans simply don’t like the Republicans candidates running in 2016, at least for now.