This exercise has been doing great things for the state of my back in recent months.
I don't get back-ache when I wake in the morning.
I get almost no back pain when driving long distances.
If I lean back over the top step of my stairs, my back doesn't crack about 15 times as I move backwards along my spine.
My deadlift poundages are up with less lower back soreness after training and DOMS.
I've put mass on the traps and shoulders.
My calves don't ache after walking long distances.
So probably one of the most useful exercises I can think of for me.