Although the 'R' number hasn't exactly been a regular topic of conversation with the people I've been encountering during the last ten weeks, when it has been discussed (admittedly only on a couple of occasions with a small group of people) the verdict has been unanimous - confusing, don't really get it, etc.
Today, England’s deputy chief medical officer said live on TV: "This virus has a natural R number of 3. One case will infect three more people."
That'll do for me and, I suspect, most others.