Most Shields have a 100% Physical Block ratio, what makes the Hollow Soldier shield a good starting shield is that it has good percentages for blocking the other elements(nagic, lightning, fire). Overall, I have found the Eagle Shield to be the best Medium Shield. The crystal Shield is better still, but it can't be repaired(though, it is not that expensive either).
As far as I know, however, the Hollow Soldier shield is the best shield(if you look at overall percentages) with the ability to ripose. Feel free to correct me if I am wrong...