Counting from his first full month as president, the economy under Obama has performed poorly. Only GW Bush, with an average monthly job loss of 25,000 the same number of months into his presidency did worse than Obama's loss of 12,000. See rankings below.
But if we discount the first full year of his presidency, assuming that inherited conditions like a post-2000 market bubble bursting or a global recession had little to do with their policies, Obama fares better in comparison. With job creation of 131k per month, the economy under him rates just blow Reagan's 135k.
It's worth noting that Republicans are far more adept at eluding dismal job creation records than are Democrats. Carter lost re-election and GW Bush won. It's an interesting set of comparisons. Will voters conclude that Obama is as bad as GW Bush (and barely re-elect him?), nearly as good as Reagan (and decisively re-elect him?) or more like Carter (well intentioned but unable to shake the label of ineffectual in spite of actual numbers?)?
Packaging matters and Republicans seem to best understand that. It's not clear, though, that Obama's campaign knows how to package his mediocre performance in the wake of such exciting promise. It still seems to me that if job creation under Obama starts trending upwards - particularly if it is enough to cause unemployment to drop below 8% - he'll easily win the re-election. If his numbers continue like this, though, the November election seems like it could be decided by the flip of a coin.