Mal-A-Ket has ketoconazole, Malaseb has miconazole. Both are anti-fungals in the same family.
Mal-A-Ket has 2% chlorhexidine, same as Malaseb.
The big difference is that the Mal-A-Ket contains acetic acid as well which is also antimicrobial and will likely aid in drying up irritated skin.