This is the best seat cushion I have owned.
I have owned four different seat cushions over the past few years from three different companies.  The Purple Ultimate Seat Cushion is by far the most comfortable.  I looked up reviews on Youtube before I purchased it so I was aware that this one is larger than most others.  It fully covers the seat of my office chair, but it is not too large.  It compresses evenly across the surface and has a nice medium cushion feel everywhere.  I can sit all day on this cushion without any discomfort that I used to get with my other seat cushions.  This one is worth the higher price!
Rating: 5 stars