bro both train have different USP and its depends upon your choice no one is stopping u to board 12582 ...
and due to its perfect overnight timing its best choice for CNB and ALD pax...yes undoubtedly its a 2nd best choice for sleeper pax for BSB after 12560..more importantly yar let it decided by the passenger's ...for me 12560 has always advantage on 12582 ...due to LHB coaches, early arrival at bsb, having better punctuality record and major plus point for working class is no body wants to reach at 12 noon and than again board the train next day evening...for 12582 its also have good priority but major drawback is its arrival time at BSB ...good point for 82 is...
more... availability of tickets ...i would also like to know your parameters on which u decided if u want then plz share.