Reasons you should like Ace McShane off the top of my head:
She makes her own explosives. For fun. Highly volatile explosives she carries in a backpack.
She beat up a dalek with a baseball bat because it called her small. A dalek. With a bat (it was a special bat but still).
Her jacket.
She likes girls.
Do you really need more?
Here’s some more anyway:
She calls the Doctor Professor (it’s adorable).
She brought Excalibur out of the lake and gave it to a soldier and told him he could be king of England.