|Cult of Vorg|
Slayer or ranger do make good sword&boarders, early access to Shield Master is pretty amazing. Slayer is more versatile damage (and more fun in general imho) until ranger gets instant enemy, ranger is brutal against their favorite favored enemy.
Before SM, you use a light shield off-hand. With SM you use a heavy shield main-hand, and a light crit-fisher (best=kukri, or maybe cestus if you go fighter(brawler)3 for feats and more damage after glorious lvl 6) off hand. That and and using shield enhancements instead of weapon (+5 bashing, everything else is gravy), means access to that feat at 6 instead of 11 is huge.
Shield Slam and Greater Bull Rush is a great combo, if you have friends in melee with you. Every hit with that shield provokes AoOs from your friends. If you're solo on the front line, you don't need those BR feats, but SS is still groovy if you can knock foes back enough to deny them full attacks.
Shield spikes stacking with bashing enhancement is debatable, I believe they overlap instead of stacking, but base damage dice don't matter much with all the static bonuses you can pick up.