Not bad, but larger than I exepected
It gets the job done, however it is larger than my car seat, so it has to be somewhat squished to fit properly.  It has yet to fully relieve my lower back pain, but I cannot blame that on the seat.  Otherwise it is a good quality cushion for the price, and has not lost its shape or form in the past 2-3 months I have been using it.
Rating: 3 stars