Which class gets the most out of a Manastone?

[Vanessa]

Was just wondering which class get the most out of having a Manastone? I know its nice on Shaman and Druid because they have regen spells which help counter it, and I also heard at some point clerics can somehow negate it with having enough hp or something? But what other classes benifit well from using one, and which class is best suited for it, which one seems to become much stronger/easier because of it?