I have a few friends from both Thapar University and LNM-IIT Jaipur and based on the reviews I got from them, I will say LNMIIT Jaipur will be a better option. Here are the reasons why.

• Batch Strength: The total number of students at LNMIIT is less than 600, so the competition will be less in this college. 
• Placements: The placement scenario of this college is excellent. Top companies like Microsoft, Amazon, Oyo, Uber visit the campus for placements. Samsung is a mass recruiter in this college and has offered packages of more than 13 lakhs per annum. According to the recent placement highlights the average and highest CTC offered to the students are 12 LPA and 58 LPA respectively. Students also perform well in off-campus placements. 
• Workshops: There are various kinds of workshops such as GSoC, mun, and many cultural and technical fests organized in the college. 
• Reservations: There are no reservations or state quotas for admission. 
• Coding Culture: The campus has a good coding culture. 

Hence, LNMIIT is a very good place to pursue CSE, but a college is just a medium and it completely depends on how you can utilize your 4 years in the college. Your success will depend on your hard work and efforts.