Well I'm a newbie so I may change my mind with time. But for me I want high loft that's really going to show the quilting. So I go with a high poly. I hand quilt but I don't do it the normal way. I pretty much go down through the material then move my hand underneath and grab the needle then shove it through to the top. Takes forever. But I love the way it looks so that's what I do. I can't work the inbetweens for anything. I can't even see the eyes to thread them.
So hi-loft poly is the one for me for quilts.