SIMSREE is ranked differently on various websites. You do not have to follow these rankings. Both institutions are equally good. 

• Cut-offs of SIMSREE are greater than K. J. Somaiya Institute of Management. 
• The infrastructure and facilities of the K. J. Somaiya Institute of Management is better than SIMSREE. 
• Both the institutes have top students and faculty is also good as JBIMS professors also visit SIMSREE. This makes it better than Somaiya. 
• The course you are choosing also depends on the college. 

One of my friends is studying at SIMSREE and said its MMS program is better than Somaiya. For PG, Somaiya is better because of its diversity.

Therefore, college rankings are not always correct. SIMSREE is still better than most of the Management institutes that provide quality education to students.