Just doing more tests with my Raiden. I just pulled Engulfing Lightning today too so that's good! (Woulda been better if i got it the first 2 times...)
But yea goblet picks are very situational. It all depends on what kind of buffs you're getting and what weapon u have. In this situation I have 2 units buffing attack and 1 buffing electro damage. So really, pick whichever one balances the 2 stats.
But in the end, if you had to choose one, choose the best substats.