Most of the time 2nd is ok, but if it's packed it can be a real pain. 1st is nice on longer distances, but it depends on where in Germany you will be starting your trip to the Netherlands. If it is in the Cologne or Düsseldorf area, then the trip to Amsterdam is only 2-3 hours. If you're going to Schiphol airport then you will most likely change at Utrecht because it's quicker that way. Most tickets allow you to transit Amsterdam as well.