I prefer using wire. I use these hangers (see photo) that lay flat against the project. I use one on the left side and one on the right, then attach the wire to them. The main reason is that some of my projects are not center-balanced and I have had some issues with sawtooth hangers not holding the work level enough for me. With the wire, it is very easy to hang the work level. Also, I don't like things to mark up the wall, so I add either felt or rubber pads to the work. I usually get the work hung so all four pads are touching the wall and this is how I keep the work flat to the wall. The small gap is not very noticeable.
There, I spent my 2¢ for the day.