1. McCain is obviously more comfortable and effective in the foreign-policy discussion.
2. Here the roles reverse. McCain is confident his positions are popular as he articulates them. Obama is timid and conventional in his criticisms of the Bush foreign policy much like McCain's critique of the Democratic economic policy.
3. They are both hitting each other on their erroneous Iraq predictions. They are both right.
4. Obama is focusing on the decision to invade while McCain is focusing on the war post-surge, for obvious reasons.