When it comes to multicore, it makes a number of decisions, I would do a lot different. It seems to aim at fine grained parallelism. Essentially, the road I am planning to take is: since all parallelism implies overhead, don't do it, and go for coarse grained parallelism.
It has a different string type, which Ocaml has for performance, and Lisp had for the same reason, and subsequently abandoned. (Lisp is fast on lists/list processing functions, and sharing is easier on series of chars than parts of strings - there was no performance gain.)
Yeah, MacOS or FreeBSD, definitely.