It's the great debate, which is better, Traktor vs. Serato? I can't tell you the other side of things as I've never been a Serato user but Traktor gets the job done, and nicely! The UI is clean and easy to navigate and can be customized in all sorts of ways to suit your style of DJing. It comes fully loaded with all the features you could ask for including 8 custom cue points per deck, 30+ effects, 4 individual FX units, loop recorder, the ability to adjust the colour of your wave forms, and that's just scratching the surface.
Best DJ and Timecode software on the market. I have been using Traktor since Traktor Scratch Duo 1. I love the fast timecode support, MIDI functions, mixer variation modes and of course the remix decks.