SIIB is the third rank college in SNAP and has a high cutoff around 98 percentile. Since SIMS admits mostly students from defense backgrounds so the quality of peer of SIIB, is comparatively better.
There’s also another parameter that you should consider while choosing the right institute for your MBA, i.e. specialization.
Another factor that is crucial for choosing a management institute is ROI. SIIB offers a poor Return On Investment if you don't get the top jobs. However, recently SIIB is seeing very good placements. SIIB is better in long term.