There are different things to consider:
Advantages to Co-ed:
If the proper rules are in place, students learn how to develop healthy and proper interactions among different genders.
Advantages to Separate:
There is now research to show that gendered schooling at about middle school level may actually be more beneficial to students because of developmental factors. Especially because as students are going through puberty, they are distracted by the opposite gender. However, if they are separate, the distractions are no longer there.
As for disadvantages:
I think the only thing I would think of is that in highly segregated societies, young people do not learn how to develop respectful relationships within society, but it should not be a basis for schooling.
And Allah knows best.