I've used good quality unbleached quilter's flannel on both hand and machine quilts. Hand quilting, no issues compared with regular cotton, it quilts beautifully but for machine quilting, be really pernickety with keeping it smoothed out and baste really well. On the scrappy I made my son recently, I did get a wrinkle - ermm, I mean KISS, or two! Other than that, I agree with other posters that it's great, so soft and cosy! My daughter's bed quilt is hand pieced and quilted and backed with flannel and it just gets better with every wash. It's 4 years old an it's washed a LOT!