Has to be both.

thers no point in playing good tracks badly or vice versa...

What you want is the finest tunes, mixed cleanly, with the djs own style, being REALLY creative and pushing djing to the limits.

If i saw someone playing good tunes but not even mixing them i would walk up to the dj booth and tell them they were shite and to give me a shot....

train wreaking the beats and i just walk off the dancefloor...how the fuk could you enjoy such noise????