I liked mine but my old saddle was borderline too small in the shoulder so it was too bulky under my saddle but it has great shock absorption and breathability! Also, it's really nice how grippy it is especially when used with one of their saddle pads! I'm selling mine!
I have one! They do seem to help with saddle fit and my horse seems comfortable with it and doesn't sweat as much. It does flatten a bit after a few uses, so I would order the extra padding just in case. Oh, and the white one gets dirty easily and is not as easy to clean.