Here is some data on the school which can help you take a call
Rankings
Ranking in Europe
ESADE 03
CASS 26
MiM Ranking
ESADE 5th in Europe
CASS 4th in UK
MSc Finance Ranking(Global )
ESADE 6th
CASS 38
Salary :
ESADE €68,400
CASS Undisclosed, but considered to be in the Top 3 salaries of UK
The rankings do a pretty good job to showcase the general prestige of the school, how alumni are performing, post grad salaries etc.
Plus as most of the resource and faculty is shared it gives a good idea about the quality of the program as well.
Coming to the curriculum
CASS Business School provides more specialization options in Finance (8 to be exact) compared to ESADE which offers a single standardized MSc in finance.
But in case you are an international student, ESADE may be better option for you since UK does not have flexible immigration rules for foreign students.
This may be a deal breaker if you plan to settle or work in the UK.
You can check out this page we created, to get some more insights into the M.Fin
https://www.mim-essay.com/blog/msc-in-finance/