Retainer jump potions don't really have much of an effect, except possibly getting more of the minions your retainers can bring back onto the market. That's about it, maybe some other "harder" to get crafting materials.

Class jump potions...well...those can have an effect on the community of the user of the potion refuses to do any research/ask about the class. My experience is mostly everyone who used them actually asks, and wants to learn to better themselves. There are definitely the others, but not always the case.