The world biggest and most famous cities are usually not the best ones to live in. They do not offer the best quality of life or the best living conditions. People are looking for a city with low levels of crime, the best climate/sunshine, the quality of architecture, public transportation, business conditions etc.
According to the most recent global livability report here are the best cities in the world to live in today:
Decades back this global city has been the most popular destination for immigrants around the world. No wonder they make out half of the city population today. Another great thing is the language. About 30% of all the people living there speak at least one more language besides the official English and French. Also, Toronto is a well known economic center and a home to the seventh largest stock exchange in the world. The economy is on a very high level since the city itself is responsible for 1/5 of all gross domestic income in Canada.
Another key factor and maybe the most important one is safety. Toronto is currently on the 17-th place as one of the safest city in the world to live in. This is very important especially if you a looking for a safe place to raise a family.