"Mount Gay is very different from Appleton?"
Yes. Read the above again. If I had to say, the Bajan rums are more whisky like, a combination of Coffey type and enough pot stilled blended in. Bajan rums can be considered unaltered and relatively pure, just a bit of legitimate E150a caramel coloring.
The big deal with Jamaican is in extra long fermentation, with the addition of "dunder" (leftovers from distillations), that has been literally stored in open pits for many years. The dunder develops hundreds of new esters and compounds that GREATLY increase the complexity of the rum produced using them.
For example a typical rum (including Bajan) may contain 30 to 70 esters, wherein the high ester rum of Jamaica may contain up to 1500 esters. In fact, in Jamaica rums are classed by the number of esters.
I suggest you take the time to read the introductory posts to each style in that section as these posts go to great lengths to explain and introduce you to that style.
