Firstly your opinion regarding IIM Ahmedabad is false. IIM Ahmedabad is one of the best B Schools with its alumni working at big firms. Your claim that 75% of IIM Ahmedabad graduates end up having unsuccessful careers is wronged.
Maybe your definition of success is a bit retarded. Success does not necessarily mean becoming a CEO, CTO, or CFO. Success depends on how much your hard work and efforts are paying you back. IIM Ahmedabad excels in this aspect as the placements provided by this B School are top-notch.
It’s the massive impact caused by IIM Ahmedabad’s alumni that big firms keep visiting the campus again and again. They know the surety of the talent and offer big packages. Apart from these, MNCs worldwide are now hiring from this B School. The brand IIMA is recognized across the world.
Now if you are confused between MS and MBA I think you should analyze your own interests. If you are tech-savvy and prefer technological work over management then even choosing MS can make you successful.