Alignment yoga classes that I teach are based on my long-standing training in the Iyengar and Purna Yoga tradition. Because of the special emphasis being put on the correct execution of the postures, they are the safest way of practising yoga and are particularly suitable for students with a specific health issue.
I also recommend alignment classes to those students practising dynamic styles of yoga, which as great as they are in their own right, might overlook proper alignment because of their flow and dynamic nature.