Briar and Mercy

After reading Boneshaker and Dreadnought, you can obviously see similarities between Priest's two books. Both are steampunk stories set around the Civil War. The two characters, Briar and Mercy, are very unique in their own right.  They are both very strong yet average women who know what it takes to get things done. Neither of the women are strikingly pretty who attract a lot of men like some main female characters. Personally, I did not see very much romance at all in either story. What characteristics of Mercy and Briar do you find the most similar? What other similarities between Dreadnought and Boneshaker did you find interesting?