Chicago is ahead of Toronto architecturally but architecture is one of the few areas where Chicago still has a lead. In most areas, Toronto vaulted ahead awhile ago. In 20+ years few will be comparing these 2 cities. Toronto will be miles ahead by then. I like Chicago but it will be near impossible for Chicago to keep up. Toronto is the fastest growing city in the Western world.
Toronto doesn't have the inventory of pre-War high-rises of Chicago but Toronto will surely reel Chicago in on the overall (old and new) architecture front. Heritage skyscrapers aren't enough to keep one ahead forever. If it were, Cleveland, St.Louis, and Buffalo would be ahead of cities like Beijing, Kuala Lumpur, and Vancouver ..... but they're not. One has to continually add new buildings to stay ahead.
In global city rankings Toronto is ahead of Chicago. By the 2021 or 2022 study, Toronto will likely usurp LA too. NYC will be the only US city ahead of it:
https://www.lboro.ac.uk/gawc/world2020t.html