Just wanted to jump I here, a lot of people (including me) use dagger OH as the increase in ambush damage, poison application, at faster auto attacks. There is a thread showing the math breakdown of this. The only argument people have is ToV vs Wsg dagger vs screwdriver. I believe the common consensus is that bis OH is between wsg dagger and screwdriver, we are not sure which one is bis yet as we are waiting for a math breakdown of 1 agi vs 1 wep speed, in the meantime I am using Screwdriver.
Tl;dr OH dagger is considered better than Sfang OH by a lot of people, the only problem is we are not sure which dagger is bis between wsg dagger and screwdriver.