Hi,

Primarily IIM Ahmedabad is an older school with slightly better network by the virtue of being older. ISB on the other hand has the best faculty and pedagogy in India, and has developed an amazing network since it's birth. IIMA has two year programmes that require little to no work experience in their pgp programmes while ISB has one year programme that mandates a minimum of 2 years work experience. Both IIMA and ISB have great placements.

But overall, IIMA is almost a clear choice for most of the aspirants.

Hope it helps.