MLton is a whole-program optimizing Standard ML compiler. It generates standalone executables with excellent runtime performance, supports the full SML 97 language, and has a complete basis library. It also has a fast C FFI, source-level time and allocation profiling, and many useful libraries.
sml/nj (Standard ML of New Jersey) consists of a compiler, compilation manager, and libraries for Standard ML. Included are CML (Concurrent ML) and eXene (a toolkit for X based on CML). The compiler produces efficient code for most popular architectures (Intel x86, Sparc, Alpha, Mips, HP-PA, PowerPC) and runs under Unix, Linux, or Windows (95,98,NT).