Buy this cushion!
I have piriformis syndrome and this seat cushion has been a great help sitting at my computer.  I have other cushions around the house and pillows, but none give me the support that this cushion does.  I have not tried it in the car yet, but the 2010 MDX has wonderful seats in it, but for a long drive in the future I will take it.  I would highly recommend this cushion.
Rating: 5 stars