I never really used companions on my first character. But Recently, I unlocked
Spoiler Cicero and Two Brotherhood Initiates
as companions. and Let me tell you, just by giving them a single, smithed dagger. At level 62. They two shot me.
I'm not sure about anyone else.. but I like to punch my companions until they attack me, to figure out if they're worth the hassle to bother with

I got a dagger in the gut for my efforts. I was overjoyed!
I do know, a Female Orc, over by Mortak? its the western most city, thats dwarven ruins. But theres a Female orc in the Orc Hold north of there, She was my Favorite companion. Once I paid off her Dowry, She uses Heavy armor, Likes to use bows to start off combat, then switches to a one handed weapon and shield when things get close
It was a sad day when she couldn't keep up with me. Almost Married her, and Orc. Almost