I have and I recommend the Kona cotton for quilt projects. The cheaper cotton was not as nice. I didn't think the Kona was super nice either, but it had the design I wanted and it has held up. I usually only buy when they have the BOGO fat quarter sales. I've also bought their jersey knit and I loved that! Nice quality, but as others have said it was pricey.
Also, they recommend you wash fabric before you use it. I suggest finishing the edges before you wash.