Sorry about the last post but I didn't read far enough. The shaft warranty is lifetime and the shaft itself is not real costly but to get the warranty honored you have to pay the dealer's labor to do the work. Now that's expensive! On the solid shaft - potentially better power transfer and potentially less movement and vibration but slightly more weight. Maybe less wear for the same reasons. Will any of these payoffs be seen in actual real use in all cases? Most likely not. Also, I imagine the solid shaft is more expensive to produce.