Obama's op-ed in the Times is lucid, nuanced and intelligent, far, far more an intellectual argument than your standard campaign trope.
Obama's op-ed does a few things that I am impressed with. Though the media has kept insisting Obama acknowledge the facts on the ground, the op-ed acknowledges those facts (crucially, the mixed success of the surge) while showing the underlying dynamic hasn't changed, and indeed, withdrawal has become a better, not worse, option. It ties our leaving Iraq the timetable proposed by Prime Minister Maliki. Note that it is the GOP plan, not Obama's, which conflicts with the facts on the ground: the status of forces deal apart precisely because the Iraqi government and people want the US to leave.
I'm all in favor of leaving, but clearly that won't solve all our problems, which is why I am also glad Obama ties it to aggressive diplomacy and help for displaced Iraqis (no word on whether he'll take the translators with us). A residual force seems a bad idea, as Juan Cole argues.
Final point: Obama ties our leaving Iraq into the greater strategic context: what is needed is greater commitment to Afghanistan. Juan Cole thinks that Afghanistan may already be as unwinnable as Iraq (we should always remember the Soviet experience).
The only way to "win" in Afghanistan is going to be big involvement with the Pakistani and with Pakistani problems. Failing this, I don't see Afghanistan a salvageable. Hopefully Obama realizes this.