I know it is way too early in the season to be talking about seeding, but I am looking to purchase a slicer seeder from either Salsco or a Ryan mataway overseeder. I searching out the information early to make an informed choice and be ready when the season starts. Where I live in Missouri many of the older yards (and some new ones) have a lot of rocks. Today, a ryan dealer told me to not bother using one where there is a chance of hitting rocks because the blades won't hold up. I understand that rocks couldn't be good for the blades and I would avoid using it on visible rocky soil, but who knows where the sub-surface rocks are? I can't see how anyone could escape hitting a one now and then. If anyone has used one, how well do the blades hold up. At $5000 I don't want to abuse the machine. Thanks.