According, to careers 360 both the colleges have AAAA+ rating which means outstanding.

Ratings are based on Placements, Faculty, Cut-offs of national / state level Entrance exams, Accreditation and Reward status and Publication record from Elsevier’s indexing database - Scopus.

In NIRF, Ranking COEP is in 24th position and VIT Vellore is in 13th position.

Both the institutes are good for CSE and provides good placements. You can choose any college according to your preference or location or choice as COEP is a government college and VIT Vellore is a private college. 

Good luck!!