I trust Delph more too. But lets not pretend its just been the 1 goal against United. I clearly remember him misjudging the flight of the ball against Southampton too. Not to mention a few others that didn't cost us.I trust Delph more than I do mendy defensively. Delph has been rock solid apart from one goal against united, although you could say it was otamendis fault. Mangala is still the problem for me.
But that's normal for all defenders. What I cherish most about him is how calm and skilled he is in possession.