According to my friends, it is definitely worth paying 4 lakhs extra at JSS or KIET as compared to studying at IPEC, NIET, or even GL Bajaj.
When you look at the three colleges mentioned above, these are average grade engineering colleges in UPTU. In case you really do not have an option and you have to choose between those three, go with NIET, GL Bajaj, and IPEC, in that order.
So, if you get a chance of taking admission at JSS Noida, you definitely should not hesitate and go for it.
Between JSS and KIET, you should choose JSS. The fee waiver seat may make you feel at peace right now but 4 years down the line, getting a placement from the three mentioned colleges will be quite difficult. These are average in placements. You will get a lot more opportunities at JSS and KIET depending on your choice.