IMI Delhi is better than IIM Sirmaur. It is a reputed and older b-school. IMI brand name is well-recognized in the industry. It has a rigorous pedagogy and a brilliant faculty base. Being located in Delhi, students get good exposure to the industry nearby.
IMI Delhi placements are excellent. According to the highlights of 2022, students received an average CTC of INR 15.23 LPA. While the highest CTC offered this year was INR 32 LPA. HDFC Life, Capgemini, BCG, Deloitte, etc. are among the top recruiters that take part in the campus drive.
One of my friends recently graduated from IIM Sirmaur, so I can give you some insight regarding the institute.
You can definitely choose IIM Sirmaur for your management degree. As the institute will be well-established in the coming years and being an IIM alumnus does offer certain benefits.