ug. i would never support investing any time (much less money) into one of those apps. they're shit on a number of levels, but i will put my dj ego aside for a second and say that Traktor is a decent look. The Pioneer DJS Digital DJing Software will also work.
but if this is an attempt to learn how to dj, buy a real mixer and a pair of turntables/cd players. not bein a dick, just sayin