I have one of my friends studying B.Tech from Amity University Noida. Here are the following points which will help you in making a decision.

• Faculty: Amity University faculty is not good. The university does not have skilled and professional professors. Their teaching method is also not up to the mark. It lacks in providing practical knowledge to students.
• Placement: The Bio department of Amity University is not good and at least 90% of its students are still unplaced.
• Infrastructure: Amity University has a great infrastructure facility. 
• Attendance: The Amity University has 75% mandatory attendance for all students and departments.

Therefore, Amity University may not be a good option for taking admission. As everything shown in brochures and pamphlets might be misleading. The ranking of the college and universities have nothing to do with its education and placement. So, before taking admission do your own research and find a suitable college according to that.

All the private universities in India, except maybe 2–3, are trying their level best to establish themselves and Vignan is no exception. If you are considering joining the university then you should know the following. 

• Fees are high so plan well before joining. For a 4-year long B.Tech, the total course fee is around 9 lakhs. 
• Second, the syllabus keeps getting updated each year. This makes covering the syllabus, a bit tricky. 
• The same faculty will set the question paper so I think getting through with good grades won't be an issue.

Finally, you should join biotech only if you wish to study MS abroad. Otherwise, don’t join the institute.