I have had this style of mat for years and never had a kid complain about the dips. I made a homemade, snug fitting cover and matching pillow for each set and my mats have stood up to the test of time. I have only had one of those rip at the seam and that was because some FOUR year old did it on purpose.

I can't see the brand of that mat very well from the picture but the brand I have always bought was Kindermat.