So I have now successfully played through as both Good and Evil Ironman Mode. Evil was Drow Rogue and Good oddly enough was a Tiefling Warlock. The main difference that I came across other than story elements and playstyle was that by going evil you effectively knock out any need/reason to go to the Underdark.
What about the Nightsong? Search for powerful items, allies and wealth? The Underdark has a TON of power and wealth items.
Arcane Tower
Kuo-Toa
Spectator Beholder
Ormeluum the Mindflayer
2 vendors In Myconid village
The Only Purple item in game right now - also in Myconid village
Bullet
Hook Horror encounter
Boots of Speed!
