I must admit that I have chosen self-healing mat mainly because of the adjective, what associations to neumodisch intelligent or even semi-organic materials has raised with me. In this regard, I was but disillusioned. The cuts can be seen even after a while still as they have arisen. They are not deep, because I have the backing not used with brute force, but it is there and permanently visible. Then you should not advertise something that can not be fulfilled prefer. There are significant 2 star deduction from my side.
Otherwise the cutting mat is thick enough stable so far, but depending on the situation but does not slip much. But for me the latter was not as significant as I can hold the mat well in my smaller cutting chores.
The division on the one hand in 'cm' on the other in 'inch' (and again in cm) and additional angles (45,60,90 degrees).
Conclusion: With minor flaws I would give 4 stars, because of the additional 2 trigger (see above) I land but in only. 2