Hi, I am from France and will try to give you a fair opinion about science po. This is a prestigious school with strong european influence. French politicians, major business executives, let's say a big part of the french elite form its alumnis. This is a competitive school difficult to enter. Generally, the school provides a solid general training, which students usually complete with other programs including business programs, law, or the national administration school (french public service school).
With respect to the MPA, I will say that the school alone suffers a deficit of international reputation compared to the other major reknown programs such as SAIS, SIPA, LSE etc...I think that the MPA is worth if added to SAIS, SIPA or LSE - because the education they deliver is very good - but not alone. If Europe is your target, science po is competitive. If the world is your target, then you want to join one of the joints proograms.