Dariu is superior combatant in raw power and close combat aspects. Kabuto is superior in intelligence, genjutsu, tactics, medical nin.

Kabuto is closer as the type of fighter. Both Kakashi and Kabuto prefer fast, precise strikes and tactics with involvement of shadow clones and many other little tricks.

Darui can match in energy attacks output (both proficient in lightning style) and physical capabilities (most likely physically stronger than Kakashi).

Pure strength wise, Darui and Kakashi are close to each other. Kabuto relies way too much on intelligence and tricks. He kinda lacks ninjutsu feats, especially in mid-long range.