What makes nicotine base a “good nicotine base”?
First of all, everybody is looking for the purest, highest quality nicotine. Pure nicotine should be as neutral in flavor and color as possible, just like the Chemnovatic PureNic 99+, not to influence the flavor of e-liquids but the PG or VG base is crucial.
What if the two nicotine bases you are comparing look identically on paper? Choose the one that tastes better or has a more neutral smell if there is no noticeable difference go for the cheaper one, or the one that will get to you faster.