Hello

Dual degrees are really worth it if you are going to continue in the branch you chose. The main reason for it is that IITs are not liberal in the course work you do. There are a lot of courses which are compulsory. ... You should not think about dual degree as an additional degree.

Firstly i would like to suggest that you should choose branch on the basis of your interest rather than the branches rank in colleges because if you are doing so,then you are going in right direction to prove yourself a winner. Both are very close to each other in overall rankings just 1 or 2 rank up down every year to one another.However Both of two differs in aspects like in their academics, infrastructures and placements .

• IITG has much better infrastructure not only in comparison of IIT-BHU but also in comparison to various engineering colleges.
• Placements at IIT_BHU is better than IITG as IITG is newly developed and alumni network is not much good as IIT_BHU has.
• THere are so many old societies as well as cultural socities.
• Cse at BHU is better than ece ,mech as more international companies visited IIT-BHU than that of IITG.

I hope it will help you 

Good luck ....