Pittsburgh and Madison are both low COL cities with great engineering schools where only a small handful of companies are soaking up all the talent. Definitely underrated.
Pittsburgh I can somewhat agree.
Wisc-Madison has a great reputation for mech/industrial/ops types of degrees.
The name of the game is to get high end tech talent. So sure, the University of Wisconsin can crank out code monkees for you. That's fine if that's all you need. But all the PhDs from the elite tech schools will sit down with their spouses or significant others to think about where to live and Madison and Pittsburgh just won't be terribly high on those lists. It's not all about the PhD that Google wants to hire, you have to have something for his or her spouse too. It's a lot easier to do that in NYC or SF. Just kind of the reality right now.
Since that was literally the subject of the conversation, the obvious answer is "I hope all of them".