One of my cousins recently completed his BTech in CSE from NIT Agartala so I have a slight idea about the branch. Many big brands as well as startups visit the campus to recruit students. Students receive internship opportunities both in and outside India. Moreover, many projects were published at conferences in the areas of Machine learning and Natural Language Processing.
NIT Agartala CSE has churned out many successful engineers. Now coming to your question, the reason NIT Agartala is underrated is because of a lack of communication and a preconceived notion that a North-east NIT wouldn't be good enough. The truth is it’s CSE department is facilitated really well and the labs are equipped with modern instruments. The crowd is also very diverse and the overall learning experience is unmatched.
So, it’s better not to degrade any institute based on false notions.