Help - line or column

[phoenix]

What do the experts do?  Melee in line or column?  Face a melee in line or column?  Or doesn't it matter?
In my experiments I think I've noticed that, with equal forces etc, the odds for the melee appear to be roughly the same whether you're in line or column.  But I've noticed in my games that almost everyone tries to melee and faces an attack in column. Anyone have any conclusive wisdom? hanks.