Some of my friends studied at Thapar University, so I might be able to give you some information about it. So before you decide, here is some basic information that you should need to know.
Placement:
Faculty: It is quite good but not the same as the Patiala campus.
Facilities:
Accommodations:
The fee structure of the Dera Bassi campus is mostly low, but when shifting focus to whether or not it is worth it, then possibly it is not. Hope this helps answer your query.