FreeForth is a small and fast interactive compiler composed of an extensible set of macros generating inline compact i386 native code, including floating-point instructions, and an easy interface to Linux and Windows dynamic libraries. It uses two stacks to pass subroutines arguments and results separately from return addresses, like other Forth dialects, but unlike them, it is a simpler pure compiler (without an interpreter) offering interactivity through "anonymous" subroutines which are executed by their closing ";" macro. FreeForth is fully documented by 100K of interactive online help. Since its first release in 2006, it has been used every day for cross-development of realtime industrial applications embedded in microcontrollers, and for PC-controlled manufacturing test benches. The FreeForth distribution includes an interactive incremental assembler for the MSP430 microcontroller family.
I've been using Gforth for 6 years, as development base for interactive assemblers for ADSP-218x and ADSP-BF503, and on top of these an RTOS with token-threaded virtual machine for RTC-communicating alarm systems, described in an EuroForth2004 article (http://christophe.lavarenne.free.fr/ef2004.pdf). Thanks Anton and Bernd!