Which hair do you like better?

You only gave two options. I have a third option. Both. I often pick the hairstyle for the clothing my female Sims are wearing. As a woman I wear my hair in a variety of ways. It's very long, even at my age, and I twist the ponytail and put it up clipping it to the top of my head when I shower, for instance. On warm days I don't often take it back down, even in casual wear. Most of the time I wear it in just a ponytail tied in the back to help keep it out of the way. I wear bangs, too, as you can see by my Avatar. So, I would go into CAS and set a hairstyle for each outfit. I will pick a casual one and keep that for most outfits. When I do formal, depending on the dress/gown I will choose something that fits the style. For nightwear, I generally choose a braided hairstyle. I have to braid my own to keep it from snarling badly overnight and out of my face, too. There was a reason women plaited their hair over the ages, at night. I will tell you I like both of the styles you have chosen. But I would still select the first one for some outfits and the second one for others.

Give yourself some options. :)