Night Train -- Naples to Venice

We are planning to take the night train from Naples to Venice -- both to save time and money. A couple of questions:

1. Has anyone taken this train? Was it safe?
2. Any luck finding discounted rates, or did you need to book standard rates for the train?
3. I was going to book directly with the Trenitalia, because the process for E-tickets seems pretty simple. Anyone have any problems with this?
   

I normally don't book my trains in advance -- but I want a 4- couchette room for me, spouse and 2 kids (its their first trip abroad, and I want it to be GREAT!)

Thanks in advance for your help!