If you are tying your quilt, just don't use yarn. It does ball up and gradually seems to loosen so that the batting shifts when washing and some of the ties may even pull out or tear your fabric. Some acyrlic yarms do not like the dryer and may melt a little or shrivel. You should also consider your time factor. I think it would be faster to just machine quilt it (especially stitch in the ditch) than to tie it. Finally it just comes down once again to personal preference and the end use of your quilt. I think machine quilting will stand up better than hand tying after years of use.