Why do some feel Obama doesn't have what it takes to be our President?

This is one of the most mature questions I have seen as far as Obama and McCain are concerned. I am not a democrat or republican. I always vote for the candidate I think is for the betterment of our country. In this case, I will vote for Obama. Thus, for this election, I am referring to myself as a democrat. I am white. I don't care what color anyone is. I don't judge people that way. I have a lot of respect for McCain's service record. I don't however fully respect him as a person, and that of course is my own opinion, which I am free to have. I voted for Bush, and have regretted it for years. I think McCain's policies are too much like his, and I don't see how he can really grasp what most American people are going through. I realize that there are many people who like McCain, and that is fine. If everyone felt the same about everything, this would be one more boring place. When you ask a question on here and you hint at who you like in this race, there are so many rude answers, I guess some people believe that they are the only ones entitled to an opinion.