It mostly depends on the place you’re from.
If you’re from north India, (above andhra pradesh), you’ll see many students speaking hindi in the ktr(katankalathur) campus.
There are a significant number of locals as well in ktr campus but vastly overshadowed by the north Indians.
Talking about education, spending a year here, I think that both campuses are equally good but vary with respect to the department u choose.
Activities and extra-curiculur vise, ktr is the better campus in a vast majority as there are loads of student clubs to join and participate in.
And if you’re a hosteler, or stay nearby, you also have the large ground you could take advantage of.
But if you’re a day scholar and commute by train or college bus (more than 30km away),then you’ll really miss out on the campus life like how I am.
If you’re a day scholar, I’d really recommend you to take ramapuram. You really won’t be that exhausted you’ll be after commuting 2 and a half hours daily when you’re in ktr campus