So I'm trying to decide if I should go for a level 20 FvS, thus getting the Adamantine DR at the end, or if I should get a level of fighter (around level 6) for another feat, which would come in VERY handy. The capstone seems pretty worthless to me, so I'm not factoring that into my decision and the extra level 9 spell is also not needed because I only need 2 level 9 spells anyway. I'm making sure to get Adamantine body at the start anyway, plus all the enhancements so I'll already have a decent DR anyway...is the 10 more DR worth giving up a feat for?