Bhelen vs harrowmont is one of the most cynical moment In the entire series.. And I love it

I like it because for the time the game actually subvert your expectations even tho it give you many hints that your choice will not be as simple at it seems to be

Harrowmont is an honorable person and if you choose noble dward origin you know he was always loyal to your father and respected you. Yet je is traditionalist and isolationist who want to keep segregationist society that is seriously worst than human nations and things go back to shit again at the end of origin...

Bhelen however is a cunning and ruthless POS who killed your brother and "may" have assassinated your father (noble dwarf) yet despite the he became a dictator he have rather progressive and less rigid vision for the Dwarven society with closer ties and trades with surface.......and if Rica become his queen we may have good reforms and even the abolition for the casteless system

There is no real reason to choose harrowmont aside from the fact that he look nicer than bhelen.... The only way to maybe choose harrowmont is of your dwarf child (noble dward origin) get adopted to harrowmont and becomes heir