When it comes down to select the right software you need to look at the HARDWARE.
Each software package is a closed environnement and works only with it's own soundcard.
In my humble opinion the Native Instruments Audio 8 DJ soundcard is still way ahead of serato.
It does not only features more input and output channels, the sound is of a superior 96kHz
sample quality. You have the ability to connect both midi in/out, this can come in usefull when you
want to produce tracks of your own too hook on a keyboard, or use the DJM800(or other midi controler)
to control specific functions in traktor scratch.
You can hook up a XLR microphone, as well nice if you're into producing your own tracks or to record samples...
The audio frequency of the timecode is 1kHz with the serato system and 2kHz with the traktor system.
See of this like a picture taken @ 1 megapixel and one at 2 megapixel. The 2 megapixel one will be more
usefull to look at details and thus making it more precise!
Traktor scratch has a better overall waveform view with minute markers which shows you exactly where the breaks are.
Although the "on the spot" waveform view in serato is nice since it shows the "heavyness" of a beat. this is actually handy
if you're into scratching and mixing R&B. That's why most R&B/Urban DJ's use serato and most house DJ's use traktor.
I'm a happy traktor scratch user since day 1 it became available!
The multicore cables to connect your setup are really handy!