I don’t even need to ponder over this question for a long time. The answer is very simple. You should choose IIT Roorkee over IIM Sirmaur for MBA. The reason being its new establishment. People don’t care if you are an IIM student unless you belong to the older ones. The new IIMs are yet to make a mark in the industry especially the likes of IIM Jammu and Sirmaur.
IIT Roorkee on the other hand is very good at placements and peer learning. Given the current situation of both institutes, IIT Roorkee is definitely the better option. The IIM tag offered by Sirmaur lacks credibility and even if it will be beneficial, it will be after some years and not right away.