I have a few friends from both VIT and Thapar. I will suggest you opt for Thapar University as it is one of the best colleges in this league.

Admission:

VIT and Thapar University both conduct an entrance examination for the selection of their candidates. However, VIT does not reveal the scores obtained by the candidates. At Thapar, admission is done on the basis of JEE Main marks. Moreover, both the admission and counseling procedure are translucent and there is no Management Quota. At VIT one can get admission on the basis of the category system whereas, at Thapar, the quality (merit-based) is given more preference.

Batch Size:

The number of students at Thapar University per branch is less in comparison to VIT where there is a crowd on a huge level.

FCCS System:

At Thapar FCCS system is present. It is a system that allows the students to choose the timings of their own classes and the respective teachers for those classes.

Although the facilities provided to the students at the VIT campus are exceptional you should not risk your academic career for mere facilities.

You should rather prioritize Thapar and try for a branch of your choice. If you do not get into it then opting for VIT would be better. But keep VIT as your second option.