Hey! I applied and got into MAPSS, Duke, and Oxford.
The general feedback I got for MAPSS was that it was a sink or swim kind of program -- it's very intense and you mostly have to things on your own. It's hands off and you NEED to be strategic from the start about professors you want to work with if you expect to do your thesis under them. And while they have a lot of flexibility, if you choose the wrong classes you're in trouble. Also, it's 250-300 students.
Oxford on the other hand seemed to have the opposite problem -- close to no flexibility. It's still fast paced and rigourous, but you get little to no opportunity to explore other disciplines. The MPhil is basically the first two years of the PhD and everyone doing it knows they want to do economics.
I personally liked the duke program best. It's a good sized class (around 30ish) and you have enough mentoring and flexibility. Duke encourages research and you can get RA jobs if you do well. Funding isn't guaranteed, but if you're a strong candidate they can offer you some need based tuition waivers. Like Oxford it's 2 years.