Both men have their strengths. It would be better for conservatives, though, if Rubio ran and Bush bowed out.
Ideologically, there’s not much difference between the two men. Both support “comprehensive immigration reform,” including legal status for many illegal immigrants, a guest-worker program and stronger enforcement measures. Bush seems more adamant on the subject. Bush differs from Rubio in favoring “Common Core” standards for schools — but that’s more of an issue for state and local governments than for the feds.
Bush’s great advantage over Rubio is that he has been an executive, and a successful one. That’s something that voters seem to like when hiring a president. But Bush is rusty. His last election was 12 years ago. He’s been mostly absent from politics during the entirety of Barack Obama’s presidency, and when he has popped up it has been to criticize other Republicans on taxes or immigration.