In my opinion, IISc Bangalore is a way better option than IIT Bombay mainly because it offers core engineering in computer science e.g. Linux Kernel Programming. It is true computer engineering. It helps you understand the science of Computer Engineering and develop a strong grasp of it.
Any science be it Computer Science or any other is solely based on concepts and implementation of these concepts is quite difficult. An extensive knowledge of Computer Science doesn’t necessarily ensure great Computer engineering skills. But it’s true vice versa. So by going for IISC, one is surely choosing the path of excellence through the very foundation of Computer Science.
IIT Bombay is a brand that is known nationwide whereas IISc is known globally mainly because of its focus on core and complex concepts in Computer Science. Moreover the quality and quality of papers submitted by IISc is much more than IIT Bombay and this already reflects how successful it is going to become in the future.