My XYZ printer is able to do both ABS and PLA but for now the printer is limited to manufacturer spools (cartridges).
I ordered a kit that will allow me to use PLA without having to wait on XYZ and so that I am not tied up to their filaments.
But to answer your question, ABS is the entry, first gen filament introduced. PLA has been showing up for a while and seems to be prefered by advanced users.
I have yet to test in my printer to see the difference.