In comparing McCain to W.Bush, while McCain agrees with Bush on permanent tax cuts, and completing the mission in Iraq (especially now that we are winning) I don't see McCain making the kind of ideological blunders that ignore reality, as Bush did.
I see McCain as reaching out to the political center more, and not catering exclusively to the conservative base (which McCain doesn't have to rely on anyway!)

Throughout the Iraq war, McCain is labelled retrospectively by Democrats as being "just like Bush". But that's simply not true.
Along with Republican senators Luger and Hagel, and Democrats like Biden and Levin, McCain has constantly pressed Bush publicly over the last 5 years to change to a winning strategy in Iraq and fire Defense Secretary Rumsfeld, replacing the Defense Secretary with someone else who would regain the confidence of the House and Senate, of our troops in the field, and of the American public. Which finally happened after Nov 2006, with new secretary Robert Gates.
And since then, the war in Iraq has improved dramatically, to the point that even Pulitzer-winning reporters for the New York Times (John Burns) and Iraqis polled, cannot deny the vast improvement in the security situation there.

McCain, like W. Bush, advocated staying in Iraq to finish the job. But unlike Bush, McCain didn't have loyalty to incompetents that he refused to fire, and pressed Bush every step of the way to fire Rumsfeld.

Whereas the Democrat response among the candidates has been retreat retreat retreat, withdraw withdraw, and abandon the Iraqis, across the board.
McCain, on that issue, by the success evident now, is to only one who got that issue right.

The new liberal mantra regarding McCain is "Just like Bush".
But that's a deliberate misrepresentation.

McCain has his problems, on campaign finance, NAFTA and particularly immigration/amnesty. But he's not "just like Bush".