When I have quilted with minkee on the back it does slip a bit, but not much. I just pin basted the quilts I've put minkee on, using lots of pins a fist apart and they didn't move much. They've been washed and haven't stretched at all, nor come apart. Straight stitching lines as your quilting works best, making "X's" through squares. I tried doing 'loop d loop's on my grandson's quilt and the minkee doesn't want to do 'loop d loops'! I found I couldn't make large 'loop d loops' so they ended up very small!
I prewash and machine dry minkee and that takes most of the shedding away--sheds where you cut it! Doesn't shed later. All minkee is 100% polyester. In my opinion, I don't think there is much difference in the LQS minkee and JoAnn's minkee. Polyester is polyester, all man-made, unlike quality of 100% cottons. You can get minkee at JoAnn's for $8.99/yd on sale and in a LQS it's $12.99-17.99/yd! I trust the feel of it more than anything.