The first one looks completely different than the other two. The latter two look like your average DAZ scene, but with better lightning. The hair needs some work it has a lot of artifacts. Might need a bit more samples.
The first one is very realistic but at the same time very of putting. It looks like you wrapped pictures of that woman on a 3D model or something. Something with how the head pose compared to the neck its off. I dont know what exactly, but it just looks weird.