Quicksilver people is always hard to find.I'm saying why not a lot of people using it.The movement speed increase is a nice unique ability but seems rarely anyone uses it.
Idk what to get.Needle shot or Antigua.I'm experienced with auto gun series and have a pepperbox and do well with it.i like Antigua because I can move while shooting.since I only find needleshot toxic needled and Antigua line have per icing I like Antigua.first some people recommend me Antigua line for vanaduke runs.needleshot seems to have more DPS but Antigua has mobility and I can shoot one a a time acurately.
Quicksilver is not being used because:
1. It's hard to get and upgrade
2. Movement speed increase is too weak and hardly noticeable
If you are a gunner, split damage is bad and Antigua should be avoided at all costs, but AP is not bad as a swordie's or bomber's sidearm. I don't think you're a gunner, though.
It comes down to preferred style. Autogun variants are not for everyone, but it helps to try them. I was one of the doubters and Callahan users too--until I built my own Needle Shot and became a believer.