He competent. He is a clear communicator of Conservative ideas and issues. He has good knowledge and understanding of foreign policy issues.
As for who has a chance, first contemplate the wisdom of Conservative governance over Progressive Liberalism. Obama has been a good example of well-intentioned Progressive ideals that live on the surface of issues, without understanding of them. Hillary proudly proclaims herself a Progressive Liberal. She also has proudly proclaimed that she will carry on Obama Administration policies. This is why there has been a sluggish economy for 6.5 years.
Conservatism, on the other hand. believes in equal opportunity, equal justice, individualism and charity. It holds in great reverence the Constitution and it's ideals of limited federal government and natural (individual) rights. Individual rights are those inherent in the people and do not need an outside enabler (like government) to make them work. It also believes in the power and ability of free market principles to make everyones’ life better. Although these are principles on Conservatism, it is also pragmatic to bend to a certain extent to non-Conservative principles that may already be in place. For instance, Social Security, Medicare and Medicaid may be over-steps of limited Federal government, but they are willing to live with them and just reform them from the bloated, bureaucratic, wasteful mess they are. Neither would it want to go back to the pure Capitalistic, exploitative days of the Industrial Revolution. Conservatism has no problem with natural inequity in life, just as long as individuals are not blocked or impeded in their rising above those inequities. The implied Constitutional mandate of the proper role of government, being the protection of rights and liberties of it's citizens, is the mechanism that support this. This does not guarantee happiness, but it protects their pursuit of it. The individual's abilities are what determines how far they can go. For those who have difficulty, there is charity, even a hand-up from government to a certain extent, but not a handout. Compassion is not measured by how many people can be taken care of by government, but by how many DON'T have to be taken care of by government, trapped by welfare.
Bush was a mixed bag of Conservatism and mild Progressivism. For anyone who wants to learn, his was a side-by-side comparison of the difference in effectiveness of each. His few Conservative policies, like the tax cuts, worked well. It was his Progressive streak that resulted in $5 trillion in additional debt (spend, spend, spend), failed prime-the-pump social stimulus (tax rebates) and the mortgage meltdown (continence of Clinton era mortgage policy). Actual Conservatives got so fed up, they gave birth to the Tea Parties. They started protesting against their own guy. They have been taking Republicans to the woodshed ever since in election, albeit letting their rage run a little out of control in a high favoring of Trump.
His blundering into Iraq...well...he had a one track mind on Iraq which led to disaster, taking a lot of effort on his part to fix. However, Obama has had a one track mind in a different direction, also creating foreign policy disaster. Hillary was going right along with it. She owns it as Secretary of State.
There are any number of Republican candidates that are ready to lead the country again, Rubio, Cruz, Kasich, Christie, Huckabee, Santorum, Graham and Fiorina.
It makes NO DIFFERENCE who we run against Hillary,she is a proven liar,theif,tax cheat,and buffoon.
WE WILL WIN
Maybe their best shot, but he has issues.
#1. He just said he'd appoint Supreme Court Justices who would overturn marriage equality. The country is 65% in favor of marriage equality. The other 35% will already vote for Rubio. He wins no votes on that one.
2. He has some serious financial issues, which includes using taxpayer dollars for person stuff.
3. HE lied about how/when his parents came here from Cuba. Trying to make them seem like "exiles," when the fact is they came earlier than that, and even visited a few times.
4. He's a Republican. They're not too popular right now.