What is best in B. Des & BE/Tech in CS.

Well, what you have to understand is that a B.Tech is an engineering degree (in one of many fields so I can't make a direct comparison) and a B. Des is not. It's focused on other things including but not limited to user experience, HCI, ergonomics, etc. The course isn't similar to those on mechanica

It depends on you college. If you are getting any good NIT or IIT for CS, then this is the best option.