"The downsides in Philadelphia are an inefficient tax structure and significant public sector pension problems. The state has its own fiscal problems, including a structural budget deficit. As a result, whether the city and state are able and willing to offer generous enough incentives remains to be seen.
However, overall the upsides in Philly outweigh the downsides. Amazon would be coming to the city at exactly the right moment: A boom is under way but is not so far along that the city is now expensive."