VDJ is better for all around use (PCDJ as well, but not as widely used). Traktor is, as Bob said, for creators, good FX, built-in scratch. It goes on sale at least once a year (usually around Black Friday) for $50. This upgrade only worth it if you already have Traktor Pro 2 (I do) and want the current version.
I own Serato DJ, Traktor 2 and PCDJ DEX RE .. I'm looking for an app that has great search capability, automixing (as necessary), video and karaoke. I don't care too much about remixing tools, beat tools, or scratching support. Algoriddim looked good, but the Windows version is inferior to the Mac version and I have more Windows PCs and it doesn't do video on a PC and no karaoke on either platform. Serato/Traktor don't do karaoke (yes I could probably use another app for the few times but I would prefer consistency). Mixxx doesn't do video or karaoke, so that one's out.
PCDJ DEX does all 3 and VDJ does all 3. My DEX RE (Red Edition) does basic karaoke but no video .. the upgrade cost to full is $119. VDJ is steep at $299, but is the god standard for mobile DJs, though Serato wins for most club jocks.