Vancouver is my favourite city in the world, though there might be some hometown bias sneaking in there.
Seattle was great to visit because it has extremely similar vibes to Vancouver all around, just somehow actually quieter. It's basically like the American version of Vancouver.
Toronto is great but too "American" feeling for me, for a Canadian city. Far too large, far too crowded, far too noisy. Lake Ontario is beautiful and the food is great, as is the thriving multiculturalism the city is well known for.
NYC was fantastic to visit. Too crowded, that's the only thing that would really deter me from visiting again. Beautiful place, majestic skyline, amazing arts and food. One of the best trips I've ever done. As a fan of musical theatre, seeing one of my favourite musicals in the gorgeous Gershwin Theatre was an unbeatable experience.
San Francisco, if it wasn't for the heat, would probably have been my favourite trip I've been on! The seafood was topnotch as was the sourdough, and the culture is really interesting. Unfortunately, I know crime has gotten quite a bit worse in the 10 years since I visited and many people have told me it's not as great as it used to be. Maybe one day I'll return to see for myself!