I must say that carnitas are the best hangover cure - period. Couple that with home made agua de tamarindo or fresh squeezed oj and you've got it made!
They are located on Guillermo Prieto - turn at Aka Si! (Melchor Ocampo) when on Benito Juarez, go down 5 or 6 blocks (you'll pass Michoacana on your left, then 2 or 3 more blocks) and turn right on Guillermo Prieto (there IS a street sign!) and park right in front - tacos are $13 pesos and the plates are $55. You can't beat those prices!
The lady that owns it also makes assorted Mexican candies - delish!