St Xavier's is the top most and one of the reputed college for BMS.and offcourse it's difficult to get in due to entrance exams.

Jaihind college, mithibai college,HR college, Podar college,SIES college, Sydenham college and Hinduja college are also good colleges for BMS.

BMS is all about managemental studies it not only depends upon college. But it depends upon the way you study and score marks.
Narsee Monjee College of Commerce and Economics.

HR College of Commerce and Economics.

Mithibai College.

KC College.

Usha Pravin Gandhi College of Management.

RA Podar College of Commerce and Economics.

SIES College.

K. J. Somaiya College of Arts and Commerce

These colleges are also pretty good in Mumbai.
Hope you got the answer you are looking for thank-you.