Originally Posted by Son of mortarion
at 1500 -2250 the lord is a better choice due to reliability, versatility, and deep strike(if given terminator armor).
How does he have anymore reliability or versatility?
If you give him the terminator upgrade, he's a mere five points from a plane-jane DP.
The chaos lord cannot strike at s6 on initiative order, he does not benefit from the monstrous creature special rule, and he can be instantly killed. His daemon weapon is overpriced, his statline is only marginally nastier than a space marine captain(who will dice you in CC thanks to his command squad.)
Meanwhile, the daemon prince is a winged horror. Whatever you run him into short of an ork swarm will be crushed into oblivion. He can easily throw landraiders aside and send marines back into the holding box.
If you deep strike a lord, what exactly is he going to do? Use a combi-weapon? Than explode violently as he can't deepstrike with any support at all? Deep striking a lord is the equivalent of throwing a vital, expensive key at a door overlooking a pit. The daemon prince is having the key already in the hole and a nice bridge between you and the door.