you may want to consider that in the US you are probably paying your own housing and utilities, and that here that would all be covered by QF. Deduct your housing costs, car costs etc from your salary at home, that will give you a truer comparison to the QF salary. My guess is that you can take off another 40% from your US salary, giving a comparable salary closer to 35 - 40K?. Then the 75K here is probably double!

btw: there is lots to do here!

the biggest concern should be getting kids in school. Start now, waiting lists are long to get into American schools.