I rarely build any of the VI units aside from Huscarles and Horsemen. Carls aren't as good as FMAAs and can't be maintained once High comes around. Landsmenn are a little better than Vikings, but not by much and again you essentially lose them in High and can't build them outside Scandinavia anyway.

I have a weird psychological hangup with Huscarles. I know they are good, but I also know that I lose them in High so I will hoard them. I'll pump them out from Sweden with upgrades, but then I tend to use them sparingly. Can't waste a single one, might need them later! They are my precioussss.

Huscarles should probably be a 2 turn build.