Scheme Implementations

So. I've been trying to learn Scheme, but the lack of a reference implementation has gotten me confused. I have installed scm, but I am still unsure. Therefore, so I must ask: What are the best Scheme implementations for a beginner? And what is this stalin thing I've been hearing about?

Racket is shit. Use Chicken or Gambit.

Guile is nice. It's less than 1MB I believe. Just be sure do this to set up tab completion and history in the interpreter.

$ cat >.guile
(use-modules (ice-9 readline))
(activate-readline)