I'll lead with my city, Indianapolis, as an example. (admittedly, a bit of a dark horse)
Pros:
Located in a very stable, business friendly state with low taxes.
Geographically centered in the US, with access to several major highways. It's called "the Crossroads of America" for a reason. Located less than a day's drive from Chicago, Cincinnati, Louisville, Columbus Ohio, Nashville and St.Louis.
Multiple colleges within an hour's drive. Indiana University, and Purdue University would be the biggest draws for tech and business grads. They also have a joint campus in the heart of Indianapolis. Smaller schools like Ball State and U of I are also worth mentioning.
Highly regarded international airport 10 minutes from the downtown core with FedEx's second largest hub.
Shovel ready site in the middle of downtown that more than meets the size needs. If they want to be in a city, there aren't going to be many other options this large for this cheap, located so close to the city core.
Cheap real estate for future expansion and for employees.
Developing a growing tech industry. Salesforce has a substantial presence already, but they're not the only game in town.
Used to hosting large conventions and sporting events
Developing social scene. It's not Austin, or Nashville but there's a lot to do now with pro sports teams, tons of museums, nationally recognized restaurants etc.
Downtown is super walkable, even in cold weather. We hosted the Super Bowl in snowy February and people couldn't get over how easy it was to move around on foot without even going outdoors.
Multiple "fulfillment centers" within a short drive.
Cons:
Politically, Indianapolis is a "blue" area trapped within a very "red" state. If you'll allow me to sterotype, most young tech workers that I know are more blue than red, so that may be a hurdle. The RFRA law authored by the former Governor was not popular with large businesses in the state but hasn't been mentioned lately.
Mass transit is way behind. The bus network is just ok. They're trying to introduce some high speed bus lines, but it may not be enough compared to larger cities. No trains or the like exist.
The airport is great, but it's currently lacking major direct flights to a lot of European cities. That seems like something that an airline could add pretty easily, but it's worth mentioning.
May not be far enough East to merit strong consideration.