I've used both of those products, but I have settled on DEX from PCDJ. The difference for me is playlist management and having 4 decks to mix from. My style of mixing works better with DEX than the other software which is why your cousin should really do a try/buy of some products to see what fits his style the best. I have since added a hardware MIDI controller to control DEX so I can do hardware mixing with DEX.