No. 1
Looks like the shutter curtain clipped the sensor?
I think it could do with some cropping, I personally would also get my doge tool, select it to lighten highlights, and get rid of the vignetting where the background hasn't blown out.
IMO you either blow out all the background pure white or you don't have any of it blown out.
Nice exposure on subject.
No. 2
Over exposed subject, vignetting, weird nose shadow from incorrect soft box position & and lack of fill. If you would have raised the softbox up a little you would have had loop lighting, instead you'v got sort of split lighting, but you have illuminated too much of the right side of her face with the main flash.
No. 4
I really like this one, although the background might be creating a little too much wrap as she's almost blending in with the background because she was too close to it. If you struggle for space, a solid grey background looks really nice, especially with a sympathetic background light, this will avoid wrap issues.
No. 3
Not bad, but has weird nose shadow, and suffer from some of the previously mentioned issues.
All in all though, not bad, but plenty to be improved upon...