The Sergeant is second only to the Vaegir Guard and Nord Huscarl/Veteran in a 1v1. They're decent, but they're basically there to soften up the enemy for your infantry to do their dirty work. The only cavalry you will see in a Nord army is Lords and the occasional mounted mercenary.
Get an army of Huscarls and you will win any even numbered fight against AI. Cavalry archers are stupidly good if you can use them, as they were in antiquity. SPECIAL: Cavalry Archers: D for AI, S for player who can properly micro them.The definition of glass cannon, they cannot hold up against Swadian or Sarranid heavy cavalry in general melee but if you can get them to repeatedly charge, their lances do work. Their only guaranteed infantry unit is their base recruit, who is garbage. Might as well share it where I can get flamed be constructively criticized by crazy people.