I have the Husq SE with sensor foot...That was the main reason for purchase..LOVE IT...You can just push the button for arrow up and foot won't raise...But your needle also won't stay down...You'll find you will love the sensor foot and always use it...When cont. piecing you'll want the needle down in the fabric and the foot coming up so you can just feed your next piece and go.
I wouldn't buy another machine without this feature and I think Husq is the only maker of this...I've heard they have the patent?