Common amongst collectors but still not out there enough in my opinion. Don't see them in the big box stores. Nor do you find General MacArthur in nurseries unless they specialize in crotons. You find some nurseries with 10-20 varieties, generally grown for landscaping. General MacArthur is usually not one of them.
To me, General MacArthur and the Tortoise Shell have sparked many an interest towards the use of crotons in the garden. "oh those are lovely, hey those are actually crotons? The don't look like the crotons my Grandparents were growing back in the day".
Just my opinion ... but hey what does a moose know?