Which Acupressure Mats have you used.

After reading about the ProSource Acupressure Mat, I went online and began a search. There are so many out there. Of course, each says it's the best, but prices range from $15 to $80. I see many of you have the ProSource. Are there any others you can tell me about? I've seen one called TimeBeWell Eco Friendly but the price is $20 higher than the ProSource Fit, and then there's the KANJO which runs $80. If I'm buying it for back pain relief, I want the best quality, but not to overpay. Help!