Is the IPM course at IIM Indore better than doing engineering, followed by management in top IIMs?

If you are willing to pursue MBA after the completion of your engineering then IPM is the good option for you as you can complete your IPM in five years while engineering and MBA together will be for the entire six years. If you go for IPM, you will have one year of job experience after six years. 

In the IPM program, you will get to learn relevant courses in the undergraduate (first three years), while the things you will learn in engineering, will not be of much use in an MBA. 

IPM gives you a chance of doing an MBA from an IIM. If you want you can also attempt CAT to get into another IIM, after 3 years of the course. 

If you are determined to do an MBA after gaining some experience, then IPM gives that option too. After two years of the IPM program, you will have the chance to work for two years. After that, you can come back and pursue your MBA from IIM Indore.