I have ridden with both saddles: If I was going coast to coast, I would go with the sprung saddle. The springs take the little bumbs out of the road that will add up after several consecutive days in the saddle.
As far as the sprung saddle making noises; I have never had any problems: I am 260lbs; so if the saddle is going to squeek, I am guessing I would have heard it by now.
If you decide to go with the B-17, try to outfit your bike with larger tires(if possible). I ride panaracer pasela 700x37 tires and they really make for a smoother ride with the unsprung saddle.