Im willing to bet the stats will be better, but the two variations of it will be ATK/MAG/MR and ATK/MAG/DEF. I'm sure that with all the people purchasing them we will be able to find out.
So far from what i've seen, the Cosmics don't have "random" stats, unless you are considering cosmics as a whole. Each type of cosmic has the same base attributes, though some have variations (as I mentioned above). The rarity and tier of the cosmic only change the stat base and scaling.