Well, it depends upon several factors. A few of them are as mentioned below.

• Where you possibly imagine yourself in the next 10 years and more?
• What has been the real motivation behind your aim for pursuing engineering? 
• What is the time period you are willing to assign for reaching your goal?

There are other factors, or possible scenarios, such as,

• Cushy CTC: In this case, CSE will be better than Mechanical Engineering.
• Higher studies abroad: CSE and Mech both will offer similar opportunities. 
• Competitive examination: In case you would want to take the UPSC examination, IES, PSU, or several others, choosing Mechanical will be better as compared to CSE.
• MBA from IIM: With regard to that, being a student from the mechanical department can give you an edge. As it will offer you diversity points. If however, your scores are low, then you will lose the edge.
• Work destination: If you want to work in Gulf in the future, then choosing Mech is better. If you dream of working in the US, CSE offers better options. 
• If you have a natural affinity towards automobiles then go for Mechanical Engineering. 

The above scenarios can give you possible average outcomes, but there can be vague contradictions as well. You also need to consider which subject interests you. 

According to various student reviews, the preference order for CSE and Mechanical is MNNIT > NITJ. You should always give preference to the branch rather than the institute. Hope this clarifies most of your doubts.

One of my friends is an alumnus of PEC Chandigarh. According to him, the Mechanical branch has good placement statistics. Here are a few highlights of the branch that may be helpful. 

• You can easily secure an average package of 6-7 LPA.
• In recent years the highest CTC offered to students of this branch is around 15 LPA. Although companies offering software-based profiles even offer 22 LPA.
• Some of the major recruiters for the Mechanical branch are JP Morgan, Tata, ITC, Hero, Bajaj, ZS Associates, Maruti, etc. 
• The placement average of the branch is almost 80% and only students with low CGPA remain unplaced. 
• PEC doesn’t have a good research culture. If you are interested in good research exposure, go for an internship at any IIT.
• According to my friend the quality of teaching is average. 

Lastly, if you have options to go for better NITs such as Allahabad, Bhopal, Raipur, etc. go for it. Many reputed PSUs visit the campus placements of these NITs and offer Design profiles.

A few cousins of mine have completed their B.Tech from VIT Vellore with different branches. With them being successfully placed, their experience says you must choose VIT among both of these. Here’s why:

• Mechanical engineering at VIT Vellore is far better as you will get better exposure there. There is a huge emphasis on students coming up with their innovations and technology.

• The quality of students at VIT can be easily compared with that of top NITs, as there is no caste-based reservation at VIT unlike PEC, Chandigarh.

In the end, it is best recommended to choose VIT Vellore for Mechanical engineering as it offers better exposure and opportunities. However, PEC is also a good college and its fee structure is quite nominal as compared to VIT. In case of budget constraints, go for PEC.

IIT Bhubaneswar is a new IIT and was established in the year 2008. On the other hand, IIT Dhanbad is an old IIT. Being an old IIT, the academic curriculum and academic flexibility are more functional at IIT Dhanbad than any other new IIT.

Many of my friends have passed out from IIT Dhanbad who were highly satisfied with their placement considering their JEE advance ranks. In the placement drive 2020, the highest package offered to the mechanical branch at IIT Dhanbad was INR 17 lakhs per annum. 

Changing your branch is comparatively easier at IIT Dhanbad. So, even if you are compromising on your branch of choice, you can get it altered to your choice once you join in.

To conclude, I would suggest you go for IIT Dhanbad.

Having talked to people at NIT Raipur and HBTU Kanpur, I have gathered reasons why students should opt for NIT Raipur instead of HBTU Kanpur for B.Tech. 

These are described below - 

• NIT has a brand value as it has a renowned name and fame, which will benefit you in many ways.
• There is a more competitive environment in NIT if compared to HTBU.
• There are more technical, cultural, and sports events in NIT than HTBU which helps the student to develop their personality and intelligence.
• NIT is a government-funded college so more funds are given to NITs, which help them to provide more facilities to the students like Advance labs and classes.
• The alumni reach of NIT is more than HBTU.
• The average placement of NIT Raipur is better than the HBTU. 
• Students can avail 100% fee waiver if the students have low family income.

The table shows a brief overview of the institutions:

Overall, NIT Raipur is the potential choice for B.Tech rather than HBTU Kanpur. Even students of HBTU also prefer NIT Raipur over their college.