ISI Delhi is a better option than ISI Kolkata when it comes to MSQE. However, if you are from West Bengal or any nearby place, ISI Kolkata must be your first preference. Moreover, if you are looking for placements desperately then it would be best suited your first option.
But on the other hand, if you want to be an economist, then you should pursue a Ph.D. in economics without any second thoughts from ISI Delhi.
When placements are looked at, then you might feel disappointed as both campuses have average placement records. Last year, approximately 31 out of 51 students were selected for ISI Delhi and only 14 out of 17 were selected for ISI Kolkata. Moreover, there is a lot of gap in the selection percentage, therefore, it can be concluded that none of them is easier.