BIT Mesra and Indian Institute of Engineering, Science and Technology Shibpur both are top rated engineering colleges of India. However, IIEST Shibpur would be better to choose. BIT Mesra have been ranked at 33rd position bye NIRF while IIEST has 21st rank by NIRF. Not only the ranking, but IIEST Shibpur is one of the oldest Institutes of India. Being one of the oldest colleges, the professors are extremely qualified and professional. Computer Science and Engineering is one of the most demanded branches in the field of Engineering and there are vast opportunity in this field. The placements are good for both the Institutes but IIEST has extremely good placement in last few years. Various Multinational companies Microsoft, HSBC, Adobe, Odessa Technologies, Deloitte, Capgemini etc recruit CS engineers. Last year, Information Technology and Computer Science were the branches with most of the placements. So you can go for Indian Institute of Engineering, Science and Engineering. Now its upto you and you must think about your passion and interest, all the merits - demerits and take a decision. You should read the students' reviews of both the colleges
http://www.careers360.com/university/indian-institute-of-engineering-science-and-technology-shibpur
and
http://www.careers360.com/university/birla-institute-of-technology-mesra