Playing a track at a greater pitch always has the possibility of introducing artifacting (particularly if the percentage increase is substantial - thinking along the lines of +/-10 / 16 / WIDE).
Having said that, I've never heard many complaints about the 1000s. If you're not on firmware 2.20 then you can download the update from here: http://pioneerdj.com/support/product.php?c=351&lang=en&p=CDJ-1000MK3&t=78