The current state of Mages on project 99?

[Iumuno]

IMO: A class that was often a dubious choice in the classic era, particularly L51+, with few or no compelling reasons to invite in a group, that is even worse on P1999 with bugged pet aggro.

Edit: Although not personally tested on p1999, here is how it went on live back then. In a group a pet could take a "share" of xp, if it did over 50% of the total damage. So say you duo with a cleric, and the pet does 75% of the damage, than it would count as an additional group member, and it will take 33% of the damage. If you duo with a mage, both pet do 35% of the damage each, and the remaing 30% is done by the mages: then the pets will take no xp at all, since none of them did over 50% of the total damage.

So there are certain group situations in which a pet can take xp, but they should be rare.