Based on my experience, the black and white lasts longer than color. I've used Polaroid 107 (which begat 667, which FP-300B is a clone of) from 1971, and while it was obviously expired, the chemicals still spread. It seems like the dyes in the color films eventually break down to where they don't transfer from the negative to the paper, causing a loss of the positive, or a strange orange-colored positive. This might not be the case with Fuji, but it hasn't been in the US long enough for me to test that.

Another advantage with the Fuji films that might increase longevity is the fact that they are packed in all-foil bags. Older Polaroid films were packed in foil-lined paper, which was slightly porous and allowed moisture to slowly escape. Fuji films are packaged in plastic-lined foil, which might lead to more moisture retention.

When all is said and done, I figure you can get at least 10 years out of the color film, and 20 from the black and white.