io9 sometimes goes overboard in their reviews. It did slow down when Lincoln got in the Oval Office but it certainly did not "grind to a halt".
I enjoyed the film. The action scenes were fantastic, the plot was a bit cheesy as expected, and the actors were fantastic. There were plenty of historical nods and jokes throughout the film, but there were a few deaths that happened too soon or too late that irked me.
Overall I'd give it a solid B.