As Sabato notes, the average prediction is that President Obama will receive 50.2 percent of the two-party vote — a much closer election than we saw in 2008, when he received 53.7 percent of the two-party vote.
Moreover, that also predicts a closer election than we're seeing right now. Currently, the Real Clear Politics average of polls gives Obama a 3.2 percent lead — less than the 7.3 percent margin he enjoyed in 2008, but more than the 0.4 percent margin predicted by the models.
If Obama retains his current lead through the election, it will be fair to say that he overperformed the fundamentals — or, perhaps, that Romney underperformed the fundamentals. But remember that the polls right now are showing post-convention numbers that may or may not persist, and that the general trend in elections is that the polls tighten slightly as election day approaches.