Having the installer to specify the features for the player was a nice touch. It's a good change of pace to have a raider companion; for some odd reason there are almost none. She has a unique look and a cool weapon (I don't recall any companions who use a chainsaw). Her references to Baja are interesting since it brings up some intriguing possibilities for the wastelands of the world of Fallout.
Just two things: I'm Puerto Rican (Latino) and I play as a Latino Courier, and it's more than a bit odd to hear her refer to my Latino as 'gringo' repeatedly. It feels like her dialogue was intended for a white Courier, which takes me out of the moment.
The other thing is that the Followers of the Apocalypse aren't a religious group. Sawyer described them as consisting of people like Communists and socialists in terms of their ideology (so religion doesn't play a part in it in either the original Fallout or New Vegas), and the ones we meet in New Vegas are doctors and medical professionals, so Rosa describing them as 'bible thumbers' and talking about 'gospel babble' was a bit odd; that would make a bit more sense if this was a member of Daniel's group rather than the FoTA.