I love the dual feed on my 770 for piecing...I can certainly notice the difference in how my fabric moves under the presser foot if I don’t have the dual feed engaged. I find that I don’t need to pin nearly as much as I used to on a different machine and when nesting my seems, they don’t flip in the wrong direction. I guess it depends on how much you want to spend to upgrade. I do like the larger bobbin and low bobbin indicator as well as the the hook system.