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...is there a huge difference in light boxes? by that I mean the quality of the light they give?
The biggest factor affecting the quality of light from soft boxes is the size of the box: the larger the source, the softer the light.
Another factor is the evenness of the light across the face of the front panel, and that can be affected by the shape of the box, the type of light mounted in it, etc.
Finally, there's the color of the light; most soft boxes are pretty neutral, at least when new, but I've seen some cheaper ones that yellowed pretty quickly and a few that looked too blue due to brighteners in the fabric.
If you stick with well-known brands none of them should be problematic with regard to quality of light; the main differences will be in quality of construction, with the more expensive ones generally being more long-lived and/or easier to set up.