I quickly looked at these. The exposure in the last should be bumped to match the rest. And the one thing I really noticed is that the horizon line is cutting into to her on each shot--this is something you probably want avoid next time, either shoot slightly above her, or just a little below.
I like the first one as well. There might be a some softness to the focus around the eyes?
At any rate, this woman's warm genuine laugh is very beautiful, and coupled with the warm lighting tones and backlit hair, make it a very pleasant image for me. I'm sure she'll be very pleased
The B&W second image comes in second place for me (also, very nice) ... I like the contrast and range/concentration of tones. But there's something a little off about the placement of her head in relation to the background.
KDThomas - Thanks! Completely agree with your comment on the head placement in relation to the background. Definitely a busy background that takes away from the focus on the subject.
Bribrius - Agreed on the location. I live in Phoenix and wanted to shoot on one of the rims near the Apache trail. The problem was that I knew how to get to the Apache Trail from the North, but this time I had to go from the South. When I finally found the trail the sun was getting real close to set. So I took an offroad trail that had the Superstition Mountains in the background. I definitely learned a lesson about proper preparation prior to shoot. BTW, this was an unpaid shoot so the model wasn't too upset or invested on location. Thanks for the thoughts!