Like many DJs recently, I've made the switch to using Serato control vinyl rather than traditional vinyl.   I love classic vinyl but it was just getting too expensive and too difficult to source the music that I was trying to source.  At first I tried M-Audio's M-Torq.  A big mistake as far as I'm concerned.  I'm not sure if I had a faulty copy but the control signals were always weak leading a very unstable playing platform.  Basically, as I used my computer, the control plates and controllers on various club rigs, the system could not handle the variations of quality and condition of the equipment used in each night club setup.  I tracks would often skip a beat because the control signal was too weak, or even worse, the track would not play at all.  I remember one gig (a very important one at one of Osaka's biggest clubs) where not one track played correctly.  This of course translates into nightmarish consequences for DJs and resulting anxiety disorders.  Not good. 

So I've tried my hand at Serato.  I lot more stable.  However, whatever system you run, whether it be Serato or Scratch LIve - the two best products on the market at the moment - you need to ensure that you ALWAYS clean your hard drives, remove any corrupted files, build Overviews for your tracks (this is especially important for Serato) and keep your tracks organised.  

Here's another tip - if you're using vinyl control plates, always clean out the inside of the tone arm (where it connects with the headshell) as the buildup of dirt and grime can impede the signal.  Also, make sure your control plates and needles are not too old.  6 months regular use is long enough. 

If this has been done you should be in for a smooth ride.  The Serato forums are especially good. Check em out!