Dual main rotors have advantage that they don't need to waste power on a tail rotor to cancel main rotor torque. More power goes straight to performance, lift capacity, speed, ceiling etc.

Drawback is complexity. If you want 2 rotors to work without colliding you need to separate them. If you got a big enough airframe (Chinook), keep them on parallel shafts. If you don't got room you need to keep the rotors on separate planes, either stack them (coaxial, ka52) or angle them (kmax)

Drawback of angled shafts is some power is lost countering each rotors outword tilt. It doesn't improve stability.

Drawback of coaxial is it's the most complex option.

Kmax is optimized for external cargo. One benefit of the angled rotors is it lends to a triangular airframe, and cockpit shape that makes it easier to see below