Both IIM Sirmaur and IIM Bodh Gaya are comparable in terms of infrastructure, faculty, academics, and placements. However, I personally know Dr. Prafulla Agnihotri, who was the Director of IIM Trichy and has now become the Director of IIM Sirmaur and I believe that he has excellent administrative capabilities and connections in the government to get things moving fast. Dr. Agnihotri played a significant role in establishing a permanent campus for IIM Trichy quickly, which is why I’m willing to bet more on IIM Sirmaur than IIM Bodh Gaya.
However, this answer is biased and I recommend you do thorough research and connect with ex-students, faculty, and acquaintances connected to both institutes to make an informed decision.