I've done it both ways. The loop is the way to go. Less string wear, and more accurate. Plus your arrow stays securely on the string with a loop. You can draw, let down, and draw again without worrying about the arrow falling off the string. Try this without a loop and your arrow will definitely fall off the string, especially with a short ata bow. That's due to string pinch. I just feel better having my arrow on there nice and secure when a buck comes by instead of barely hangin on.

The metal loop is a POS IMO. On my Hoyt it would hit the tec riser and scratch it all up. It chipped the paint right off my bow.