Relic +1 or ?????

[Sinth]

Relic + 1.

Weapon damage will always be better than any other stat for DPS.

Unless the primary stat bonus from the other gear exceeds the flat DPS gain from the weapon, such as Wyrm Mail piece for DRGs.
Gae Bolg +1: +2 flat damage +4 STR +3 Crit +4 VIT (over base relic stats)
Wyrm's Mail: +9 STR +6 DET +11 VIT +24 Crit -19 Skill speed (over Darklight Cuirass)

The Wyrm's mail choice will net slightly higher DPS, as the STR + DET + CRIT > Flat DPS + STR gained in both items respectively. Additionally, the Wyrm's mail choice provides more durability through higher defense, determination, and vitality. A stronger weapon does not necessarily mean more DPS when compared with other gear slot gains.