Racket has some of the same properties. But it lacks the performance and simplicity. But with Racket you gain other things like more powerful macros, an integrated environment, and perhaps more libraries.
Racket is a little too complex for my tastes. It's a little too big, a little to exerimental, a little too complex, a little too magical. I lean towards R7RS and CHICKEN myself, which are on the opposite end in terms of Scheme implementations. Guile's nice too.
Yeah, but Chibi, CHICKEN, Gambit, and Guile are all excellent at FFI, and fairly good at embedding (although for CHICKEN and Gambit, it depends on the given value of embedding... That's more Chibi and Guile's forte, as it was for SCM, SIOD, and TinyScheme before them.)
