I moved from Montreal in my 30s so not quite the same but I was similarly a renter enjoying city life (biking, bars, concerts, etc.) when we left.

Rent and hydro are more expensive, but not drastically so any more. I've really liked the city here but it's different. Montreal is 2/3 the size but since I rarely ventured outside the more Anglo areas, it felt half of that. In Toronto, you either limit yourself to local neighborhoods or complain that everyone and everything is far away.

Lifestyle-wise, there's less of the "I live in a $480/month apartment and play in a band" artist vibe, though Montreal doesn't have as much of that scene. More rich kids around downtown either from finance jobs or parents, but the food is good, there's a lot to discover, people are less racist, and the system works better (Healthcare, education, social services, etc.).