Rather than asking which is better IIMA or FMS you should be asking what is better for you.
My friend is an IIM Ahmedabad pass out. She had got offers from IIM Calcutta, Lucknow, and FMS as well. Yet she chose IIMA because it was her dream college. One year into IIMA she realized some major shortcomings.
The only significant feature here is its excellent placement. This is also the reason why it attracts so much crowd. But this fantasy is also short-lived. As soon as you land a job, you have to start paying back the excessive loan for years. For instance, you land a package with CTC 20 LPA. The in-hand salary would be around 1 lakh and the EMI standing at the end of every month would be 50000. After reducing EMI and personal expenses you get little for yourself for several years despite your hard work. Despite graduating you will be stuck in the same life for years.
Now considering FMS it has the following merits that make it a tad bit better than IIM Ahmedabad
Your batchmates from FMS will be enjoying life, and fulfilling their dreams and you will be still stuck in the same circle of paying back loans. So the brand value is just not enough. I don’t think spending 20 lakhs on any Indian B School is worth it.