Weapon damage is worth quite a bit. For threat generation I think +1 was worth it. Also, the dps increase doesn't hurt either. With Curtana +1 and 366 strength, one of the guys in coil last night was parsing me at 120-140 dps (with shield oath on!). For turn 4 that extra bit of dps is quite nice. (I understand parsers aren't the best but still, he's parsing me at a not-insignificant amount of damage and if its even close to true that's pretty nice).

I won't say Curtana +1 is necessarily worth it over something else, I don't know. I just personally decided to wait on myth armor and try for some allagan first (chest drops turn 1 which would be really nice to not have to buy with tomes).