In PureScript, how does List differ from Array?
What are the reasons to use one over the other?
The representation for Array is a JavaScript array, whereas List is implemented as a cons (linked) list.
Lists have better performance characteristics when being built up item-by-item, or iterated over by taking an item from front each time - basically List has O(1) cons and uncons, vs O(n) for Array.
Take a look at the documentation for Array and List on Pursuit for more information about the running time of various operations.