If I'm not mistaken the 635 and the 730 both have the 9mm stitch plate giving you almost double the size on your decorative stitching. The 630 features the 5.5mm. The 630 and 635 do both have push button start for regular sewing which is a favorite of mine. My choice would be a 9mm capable machine with the push button start for sewing...which leaves us with the 635. Good Luck!