Contrary to all the other reviews this is firstly not the Mk2, it's the first edition; and secondly, most people will need to buy an external 5.1 soundcard separately in order to preview tracks on the opposite deck via the preview button.
Just wanted to clear that up in one fell swoop of a review. In terms of the level that its aimed at, only beginner bedroom DJs should really buy this. Hercules seem to suffer from some hyperbolic marketing syndrome where they advertise it to all and sundry. No professional DJ would seriously be able to use this. The actual body of the box is flimsy, light and shoddy and feels like it was made in a design tech class with some copper wires and soldering irons. Most importantly however, it is not compatible with Macs (as i disastrously found out) despite Hercules advertising it as being so. Macs (or at least the new generations) simply don't recognise them when they're connected - and by the sounds of it, neither does Windows Vista.
If you're wanting to get a decent bit of kit then I'd recommend the Mk 2 and nothing lower than that. Even better for 'computer DJs' wanting to show their faces at clubs and avoid all the faffing with external soundcards and connecting to larger soundsystems, get an all-in-one like the Hercules DJ Console RMX or the Numark Omni Control. Sorted.