imbued granite spaulders vs barbed dragonscale
 

which would be the pick on a knight character in their 30-40s??? .. both similarly priced

If you can wear them, the IGS are awesome. 20ac and resists. That is just awesome.

Heres the problem. The only worthwhile knight combos are dorf pally, ogre sk, troll sk, Iksar sk, and none of those classes can use the imbued granite. So barbed dragonscale is the way to go.

Not sure how you equate 'worthwhile'.

only one of those knight races can robe, making it an objectively wrong opinion overall.

FTFY

Clearly the OP is a race/class combo that can use the IGS, and most people in that situation would wear them.

Wear both depending on situation. That's what I do on my bard.

Barbed shoulders are great to use for the stats but their AC is terrible

I switched to Dragonwing shoulders from Western wastes for the raw HP, mana and high AC.

IGS hard to beat. Resists are always good to have and the AC is solid.

As a knight, your only real benefit from the Barbed shoulders is the STA and PR - there are better options for AC/DEX/resists. Your DPS is low enough that stacking STR should basically never be a priority.

Dragonwing mantle is a thought , but for the price comparison would have to get reinforced 12ac 35 hp/mana , heavy being a couple thousand more , maybe that's the comparison ??