BITS-Pilani is better. Anyday and everyday.
Having said that, I also think that we are only behind Pilani campus in terms of quality. And we started 20 years late too, in 1984. Hopefully, if we can control some of the factors (increased seats every year won’t improve the quality of the output, increasing your research paper count by publications in stupid journals won’t help either, and many other), we might catch up. But if we remove the hypothetical situations, yes, BITS-Pilani is way better than VIT Vellore, as of today.