Which university SRM, VIT, VTU-Amirtha is best in Tamil Nadu for engineering studies as well as placement?

Its depend on you that how much you know about your field as both VIT & SRM are good & have the best placements colleges in south.

I would suggest you VIT campus in terms of academics and placements. The campus is well and great. As far as my experience, you will have a better feeling to study and get trainer well for everything.