As you are not branch specific, just go for IITR . It is really a good IIT and you will have good exposure there. Placements will also be good. But yes, I dont think, keeping BITS, (cse,ece) aside is a good option, Your BITS score is really good and please do think about it again! Or else, you will ofcourse get a good IIT with other branch options.
Hope you'll choose the best option.