This review is based on usage within a caravan awning, but I suspect that it would also apply to tent campers as well.
They are made of a dense, dark grey foam and have a good, tight-fitting interlocking design that works very well. When the surface underneath is not smooth, such as a typical caravan-site hardstanding, they still remain locked together and do not pop up, avoiding any potential trip hazard. This issue was my main concern before purchase and, to date, has proved unfounded.
The comfort factor was a very pleasant surprise and even better than we'd hoped for. Stepping out of the caravan with bare feet, onto a hardstanding with these tiles in place, was a pleasure with no discomfort whatsoever.
On one occasion, we were pitched at the bottom of a site where it rained hard for most of the night. Water had flowed through the awning and under the tiles but, to our surprise, the tiles didn't absorb the water. The muddy water-staining, left after the rain, came off with a damp cloth and left them looking as new.
These tiles have proved an excellent purchase and I wouldn't hesitate to recommend them for this particular application.