DT lines are easier to mend and you can turn them around when one end gets worn out (I have turned a few around and not found the coating on the other end knackered, others may have had a different experience).
Someone will pipe up in a minute and say that the first 30 feet (or whatever length it is) of a WF and the first 30 feet of a DT weigh exactly the same and therefore presentation will be identicle with both lines. This is all very well but I think in the hands of an average caster (one like me) DT's do land more gently for the simple reason that they slow down quicker on the shoot. The thin running line on a WF doesn't slow the line like the thick belly of a DT and hence WF lines can land with a bit more of a splash (they are going faster).
Of course this is more to do with sloppy casting than anything else. A good caster will land each as gently
Andy