Hello student, 

Considering basic sciences as the career, the institution can't be compared. NISER has got best of facilities, laboratories, faculties and at the same time UM DAE CBS got its campus in Mumbai and most of its visiting professors are from TIFR Mumbai. NISER is better as it got permanent faculties. NISER got nearly 130 seats which is higher than UM DAE capacity. 

Cheers!