Lived in both, chicagos weather is a million times worse. Yes Pittsburgh is gray, but gets nowhere near as cold as consistently or dramatically as chicago. (Pgh people think they know winter but they have little idea hehe). Public transit, as has been said, is variable depending on where you live in pgh but nowhere as reliable as the L. Car is whatever you prefer, I have lived years in pgh without a car working all over the city. Just try to picture most city’s public transit in the 90s, that’s Pittsburgh! You would enjoy the urban hills here, it’s quite a playground if you like them. Biking is fun too