The two mods are entirely different in structure. One adds weapons that are buy-able only, the other is more of a treasure hunt with some really nasty guardians.
While Elven Weaponry indeed has a shop it also has treasure hunting and some really nasty guardians. Otherwise I wouldn't have listed it, because the ones I listed are the "questmods" with nice risk vs. reward that I like and also think blend in well with OOO. So in fact they are rather alike - except Elven Weaponry
also has a shop. If you haven't met the guardian of Ithildin you've missed something.
Thinking of it, I should also add:
Gah Falquan Umarile - Awesome weapon replacer for Umaril, for those who run KotN. Fits perfectly with OOO as it has Ayleid Meteoric Iron Weaponry by the same author merged.
Mighty Umbra - Weapon/quest replacer for Umbra. Combined with OOO's boosting of her in FCOM_MightyUmbra it makes for a challenging experience to say the least.