Sidi Ifni is a bit like the edge of the world in Morocco! This little town on the Atlantic coast has lots of charm. During atrip to Morocco, I recommend staying in Sidi Ifni at least several days so as to absorb the unique atmosphere of this town and the region. Don't hesitate to rent a private house, lots of local people do it and it's a very economical way to stay there.
The beach in Ifni is particularly pretty, and it's very pleasant to swim there in summer. You must however pay attention to the currents which can sometimes be very strong and make sure you don't get swept up in them.
The market in Sidi Ifni is very joyful, animated and pleasant. You'll find typical souvenirs from this southern Moroccan region there, and magnificent pottery.