First off, John McCain will not attempt to over turn Roe V Wade;
"I'd love to see a point where it is irrelevant, and could be repealed because abortion is no longer necessary," McCain told the Chronicle in 1999. "But certainly in the short term, or even the long term, I would not support repeal of Roe v. Wade, which would then force X number of women in America to [undergo] illegal and dangerous operations."
John McCain voted to publicly fund abortions, but pro-life websites will vote to funding amendments for public funding, that he voted against. Problem is, the bills were to increase funding on womens health issues overall. However, he voted in favor of the original bills.
John McCain went behind the backs of the GOP leadership in Congress, and made a pact with democrats, not to vote for pro-life judicial nominees, in exchange for not using the nuclear option, which would've removed the option of filibustering.
On the abortion issue, I truly believe, there is little difference between John McCain and Barrack Obama, except that McCain uses the issue for political purposes, where Obama, believes the government needs to stay out of the issue.
Both McCain and Obama, oppose gay marriage, but support civil rights of same sex partnerships, and these don't include just gay relationships, but couples who are friends who watch out for each other.
John McCain would use the US Military Power, as his foreign policy.
Obama is intellectually connected to the cultures of the world and would be a better diplomat.
John McCain is ill-tempered, and would create a division even among his own party members, which he titled himself as a maverick, but others call him a name I can't use.
As a leader an a person who has what it takes to unite the country, I think Obama beats McCain hands down.
Jim