I like both of these. The warm feel like she determined. The cold one feel like something tragic has happen and she's out for justice.

Man, the lighting on this is impressive, well done.

I also like the warm version.
It gives me a feeling of determination and hope. As if the character has a goal, that she (it's a she, right? could be mistaken here) has chosen the path of a honorable warrior for the good of someone else. Kind of reminds me of an OC I created a while back and how it helped me discover a part of me I never knew I had.
The cold one gives me a feeling of loneliness and distance. Makes me think maybe the character has lost all hope and is throwing herself into physical and dangerous work so she could maybe feel alive while risking her life. Or that she has chosen the path of a mercenary trying to forget (or atone) something. Or even to try and cope with her feeling of a deceased family member who was a knight. Also, she seems sad for some reason, and desperate.

There are all sort of possibilities and feelings coming from the two picture. Many thoughts cross my mind when I look at them. Good ones, bad ones. Maybe I'm just thinking too much, maybe it really is just a simple palette switch with nothing behind it. But that's how I feel about them.

I prefer the warmer colored version, it has a bit more color to it, as to be expected from the palette used.