As I mentioned, I've experimented with both. I have my 14" (that I use out the front) adjusted with no contact and my 17" (that I use out the back) setup with light contact.
To be totally honest I can't pick the difference between them. They both cut well and both appear to have maintained a nice edge considering the amount I use them. If we were measuring the differences with a microscope on a professionally maintained green, I think we
may see a difference one way or the other. In the real world on a home lawn, I really don't think it will matter.
Due to the fact that the no contact method will put a little less strain on the mower itself, I would still lean towards a no contact method personally.
But I do like a can of worms!
