LBrown, I can see where truck bed mats would work, as well.
Anything flexible, yet tough enough not to abrade away too quickly.
MJP, hadn't thought about it, but yes, the "old world" is full of cobblestones, and pavers/stone with a lot of seams, a real nice place to get use of a flexible edge.
The other thing that was brought to my attention was the use of Non-Marking material. It's worth a quick test somewhere, to make sure the rubber isn't going to leave a black skidmark down the middle of your white concrete driveway or your decorative colored cobblestones.
On the asphalt pavement I wasn't very concerned.
I used a steel edge for about 20 years, worked OK, but now that I have seen what a rubber edge will do, I will only go back to the steel if I'm trying to tackle packed in snow and ice.
My key to effiective snow removal on pavement is NOT to drive on it, plow first.
Today, coming home from work, I noticed some of the local driveways that had not gotten a lot of effort, well some had gotten NO effort, and had been driven on and mashed down. They are now covered in icy frozen solid tiretracks. tsk tsk tsk. Good way to fall and get a back injury for life.