I can't remember the stats on the other cores at base legendary, so hard to say.
Looking at this I'd guess high HP (like 1100), ~240 energy, ~100 regen, 193 heat, 72 cooling.
It seems that right now 3 or 4 of the cores are relatively balanced, and the best one depends on the type of mech and weather the extra weight is a big hindrance. I haven't seen all the new stats, but Windigo seems best for heat/physical and Grim Reaper for energy. Cores like Brutality, Naga and Nightmare may have their place depending on weight constraints.