I just returned from Amsterdam. Be forewarned, and if you are traveling into the city from the airport, hang on to your ticket. You will need it to get out through the turnstiles. Also, you can no longer get into the center/rail section of the station, unless you have a ticket to open the turnstiles. If you have a OV Chipcart, it will open the gates and will not charge you, unless you stay longer than an hour. (is my understanding).
Does anyone else have any more information?
My daughter and son in law live in Amsterdam, and they didn't even know about it.