I've never actually saw a pot my self, but it seems like a great waste of money. I know that they can increase stats and all, but they are expensive and only last for a half an hour. If you only plan on doing a dungeon or doing tmq once then I'd say go for the pot. Human and namek pots are really good, I don't even know if Majins have pots, but its not something I'd use. Pure Majin is less based on strength and speed and more about being able to spam attack the hell outta your enemies. If you can do that your attacks can be **** and you'll still kill mobs.