Though Abacus and ANSYS both are useful for non linear analysis it depend upon the various variables. I am using ANSYS for pipe joint analysis due to its suitability, flexibility and efficiency.
I think it is just a matter of preference as both these software match one another in their capabilities (at least in the basic sense). For nonlinear Reinforced Concrete simulations including blast loading, I would prefer formulating the problem on Abaqus.
Before ANSYS Workbench when the comparison was between Ansys APDL and ABAQUS, ABAQUS is the best because of it's interface. but after ANSYS Workbench version, i thought that ANSYS is the best. input and output become very easy and fantabulous.