Is mob XP based on the level or the con of the mob?

[Kika Maslyaka]

on level of mob.
the con only represent average difficulty of encounter - such as Dark Blue = "It can still kick your ass" [You must be logged in to view images. Log in or Register.]

thought system is heavily inconsistent. As you go higher, the mobs become so much more deadly, that the only thing that matter is actual difference in level between you and it.
At lev 60, a lev 59 blue con will beat the living crap out of you in a matter of seconds [You must be logged in to view images. Log in or Register.]

At higher levels there are instances when its easier/better XP to chain pull light blue's, than a single dark blue - specially for melee classes