Im in the DS trainer 18 and find that once I go over about 14 miles that they beat up the soles of my feet pretty bad.
I did a 16 miler at the weekend that had a pretty messy last mile due to my feet. I overpronate but support wise the DS trainer works well for me, more agressive support shoes like adrenaline give me serious issues when I start to hit the 20 mile mark.
So in summary im looking for a long run shoe, with some support to compliment the DS trainer.