Who is we?
> Arrays, use implicit ordering, and without the overhead of object
> headers and pointers, quite a few more elements of your data structure
> can fit into a cache line. (That is, the good old memory hiearchy.)
Array's vs Lists are (as most things) a trade off. For example
inserting an item into a list is O(1) while into an array is O(N).
Also lists can be handled in a imutable fashon while arrays tend to
require mutable memory.