as for 'MP3 shit quality' as DB says, check the pa's of most clubs.. average at best.
ive seen some 'professional' djs ram mixers into the red, push the compressor too far, then pull me about 'that shit pa you made me play on' i mean, ffs, dont u know red is generally a bad sign ?
and i use WAV every time. i dont have a lappy, but given what i used to take out for hardware live sets, a pc is a doddle.
the whole argument is pointless imo. whats more important ? the means or the end ?