Hey!
I am an ESSEC Student (France Campus) currently in London doing exchange semester at KCL. Similar to you, I am also going down the path of Investment Banking.
ESSEC is a good school, the program itself and its design sets it apart from KCL & Warwick imo. It is a target school for IB in Europe. You will get the chance to study abroad in many universities and there are several different tracks you can choose inside the program (Like UC Berkeley, IBEA which invovles studying in 4 semesters in 4 different countries and so on). As for the Singapore campus, it is way smaller that the one in France (you will have to do one semester in france anyway). But I have mostly heard good things from there (some of my closest friends were from there).
If you are sure that you want to pursue a career in IB, I would strongly recommend KCL or Warwick (both of them are pretty much similar in value, even though KCL is a semi-target) given the additional networking and alumni access you get if you want to work in London. Also the courses are only 3 years and you enter IB much sooner than ESSEC.
So I would suggest ESSEC for a more broad and international uni experience and KCL/Warwick if you want a higher chance of IB right out of undergrad.
Feel free to ask any questions!