ISIC or a city pass


I’m about to travel for a month in europe with a friend.
We are both under 26 yo and I’m also have the option to have an ISIC…
We are strting our eurotrip with topdeck’s balkan blitz and from Buapest we are travelling to Munich, Prague, Berlin, Amsterdam and London…

From your expirence, should we take a city pass in each city or shold we both have the ISIC and the IYTC? wich card will have the most value for our money?

We are planing to visit museums, parks and main attractions in every city.

Thank you:)