If you solely consider studies as the basis of the selection of an institute for your career, I don't believe there will be much of a difference. 

• The chief difference arises because the colleges were established at different times. 
• As time goes on, new clubs emerge at institutes that improve with time, the festival improves, and norms and culture unique to the college change over a period of time. 
• Because CU's engineering programs are newer, they may have certain disadvantages for several fields. 
• You may claim that you are unconcerned about everything other than your academics, but once you enroll in a college, you will realize how vital everything is. 
• Kalyani College does have a far larger student body than CU, you will have a diverse group of students in your batch. 

Also remember, that usually everyone despises their own university no matter how good or bad it in reality is. You surely would not want a gloomy college experience. So do your homework before deciding on an institution.

It all depends on the candidate’s decision. What may seem productive for him might fall flat for others.

Here pointing few specifications which might help you choose:

• IEM is a Private engineering College whereas; KGEC and JGEC are government owned colleges.
• Annual Tuition fees are far less for both the government colleges and IEM being a private institute holds higher fees and increases cost of living.
• Being government owned colleges (KGEC, JGEC), the student from financially weaker section is subjected to stipend, half-fees and full fees consideration.
• If we take a look at the campus location, IEM is situated in sector-V, in the crux of the IT revolution which began at Kolkata. Whereas, KGEC, JGEC have their own campus located outside of the main city.

IEM being a private institution is strict with its studies. But, being government colleges students can see little slack on education in KGEC and JGEC.

If campus recruitment is the sole criterion, then IEM stands out with a virtuous record. Whereas KGEC and JGEC in can see slack in core branches recruitment.

IEM being situated in the heart of the city’s IT sector, all the companies take interest to see the students from IEM. KGEC and JGEC located outside the main city.

If you compare KGEC with JGEC, KGEC is the way to go. KGEC has a better ratio of placements, infrastructure, facilities, and faculty than JGEC.

Choose KGEC if you want to study in any core department. Otherwise you can choose between JGEC and IEM for other departments. If you are looking for government jobs, KGEC is the one. Choose KGEC without hesitation. If you don’t get a chance to get into KGEC go for JGEC as both being government colleges gives less burden of fees and expenses.

Finally, it’s up to you to choose any one among the three engineering colleges. Based on the parameter, it drives your decision. My suggestion would be go for KGEC and if not then, JGEC over IEM.