It is not right to say Gujarat Technological University is not good. I have a few friends from GTU and according to them, GTU is quite good in terms of syllabus and teaching schemes. 

However, your experience will also depend on the institute that you are choosing. The faculties at LD Engineering college and VGEC are very experienced and they also teach well. 

It really comes down to how you are utilizing your years at the institute. Overall, GTU is decent and you will have good opportunities at the institute.