Hey there,
Congrats - amazing success!
From working with many colleagues from that office and having some contacts from b-school, I can tell you that the benefits as mentioned by others are better at McKinsey, yet, the downsides are shared across all firms.
Hence, McK is the top choice for you.
For me the biggest benefit is (and that is different from the other two and mentioned here incorrectly), international mobility should - at least in post-covid times - be easier since McKinsey operates a global staffing model with a global PnL and you have significantly more leeway and also personal responsibility when selecting your projects (driven by the slogan 'build your own McKinsey'). While in India this might be interpreted more narrowly it is still a big factor and differentiator.
For instance, I worked on a project in Europe with an Indian EM (project manager), who then even transferred to a European office permanently.
Cheers,
Florian