If it is Marine engineering you are looking to pursue, then definetly go for Cusat.

For other courses, karunya is a little costlier compared to Cusat.

Both the colleges are pretty good with academics, infrastructure, campus placements etc.

It would be wise to make a decision depending on the location.

For more info visit the following links:

1. https://www.careers360.com/university/cochin-university-of-science-and-technology-kochi
2. https://www.careers360.com/university/karunya-institute-of-technology-and-sciences-coimbatore