Tried them for the first time today, INCREDIBLE. Had it set up so it provided a slight "slingshot" at the bottom 1/3 of the movement, but no tension from the upper shins to lockout. That bit of assistance really allowed me to up the weight and explode up quickly and was a nice change from the ordinary.

I highly suggest you give them a try, a bit of an ego boost, but I can see them really helping your lockout in the long term.