I also like the Creative Grid Rulers, I have a 6.5 x 12.5 I use all the time. Would like to invest in teh 24" as well, they have grid and it really does help to keep the slipping at a minimum. As far as self healing mats I am not sure if any really do self heal. When it is just too bad to use on one side turn it over they won't have the lines,I really only use the rulers for my measurements anyway.