Which OPK brand is the best??!

Andreea
So AF decided to come right on time today!! 😫😫😫 it's time that I jump on the band wagon with OPKs! I've never used them so which brand is the best and when do I start using them??! Thanks 😘 Oh I also started taking Gerital pills a couple days ago so hopefully that does something. Any success stories with using Geritol?!