I have had this for years, despite only recently have gotten a TRX.
I really like its size (4x6 feet), the firmness of the material (enough give that kneeling exercises are comfortable, but not so much it's unstable), and the 12" spaced foot position markets are endlessly useful, I didn't realize how much I would come to like having them there for consistency.
I will say that sometimes -- when I'm sweaty, mainly -- my hands can slip on the mat, but not (yet) catastrophically so.
Performance
Value
Build Quality