JAWS 3 3-D is a big-screen entertainment in the best Hollywood tradition. It has a good story to tell and plenty of suspenseful action. Whatever its faults -- and there are a few -- the film was a major studio production and an important theatrical release in 1983. I saw the restoration DCP projected at a midnight screening in Hollywood in September 2013. It was a sold-out crowd-pleaser. I wish more had been done with beautiful babes in bikinis, and to iron out convergence problems, but those are minor complaints. I thoroughly enjoyed the film and so will everybody else.
I also didn't know they switched over to green screen that far back.
The electronic compositing of film was certainly cutting edge at the time. Bluescreen is just one of many film compositing techniques, and it became popular because it did not require special lights or emulsions. Extracting mattes was based on the fact that red and blue are opposing colors. That is, a blue filter will darken red objects while lightening blue ones, and vice versa for red filters. By combining positives and negatives of filtered shots, traveling mattes could be extracted.
While blue (or any color) will work for electronic compositing, blue is the least portion of a video signal, thus making it the noisiest. Green is the major portion of a video signal, and so became the ideal color to use for "chroma key" (known in the UK as "color separation overlay" or CSO).
