Mumbai is one of the biggest and most expensive city of India. I visited Mumbai recently and it was a really bad experience. There are a lot of place in Mumbai to visit like marine drive , a beautiful , jogging track where you can sit and take the view of beautiful Arabian sea, gateway of India , not that good but if you like historical monuments then gateway of India is for you. Juhu Beach , gurgaon chowpati , band stand , so many good places but if you will talk about living in Mumbai so I won’t suggest that Mumbai is a good place to live , because life is so fast over there.
You will find a huge crowd in the city and worst part of your life will be local travel ( you will prefer local to avoid traffic but this won’t be a good option if you are new in Mumbai ) . The toughest part will be entering and coming out from local train. If you want to visit Mumbai then it is good but living in Mumbai is really tough.