As with nearly every other DJ program, Digital DJ 2's interface is based around a library, two players/turntables, and a balance control to manage the output level of each player. You load files from the library into the players, play them, and do your cross-fades with the balance control. Also on hand are other DJ essentials such as cue for auditioning, one-hundredth second precise alignment forward and back, waveform display with loop marking, individual tempo and volume sliders, and so on. There's an entire section dedicated to looping as well.
I have two very minor complaints about the Digital DJ 2 interface. First, it lacks tool tips--those little hints that pop up when you hover over screen elements and controls. Their absence makes it a bit harder to get up to speed, though it should still be very intuitive to anyone with DJ experience. Second, I'd like to be able to right-click and send all the files I've selected in the library to a new playlist. As of now, you must drag them to an existing one.
As far as file support is concerned, Digital DJ 2 understood WAV files up to 96 kHz/32-bits, WMA, MP3, Apple normal and lossless, OGG, and FLAC. It didn't recognize APE, and it loaded, but wouldn't play, Windows lossless files--but those are two rarer file types. Digital DJ 2 ships with and utilizes the free ASIO4ALL audio driver, which reduces the latency of your audio system down to around 5 millisecond. Though adequate for playback, the normal WDM audio drivers respond far too slow for implementing real time FX such as tempo changes or scratching.
A DJ's most important talent is people skills--knowing what a crowd of people want, what they will react to, how they'll react, and when to press the right button. Digital DJ 2 will only provide the button, but it does so in a very comprehensive and logical, if not glamorous, manner.
Note: The Download button takes you to the vendor's website, where you can select the correct version for your system. Also, the audio drops out every 4 minutes in the Digital DJ 2 demo, but it is otherwise feature intact. Take it for a spin (very bad pun intended).