Well, comparing Inferno and Plan9 only makes sense to a certain degree. Inferno includes a VM, and it was designed to compete with Java, whereas Plan9 was conceived as a replacement (or evolution) of UNIX.
It makes some sense from the point of view that Inferno contains some design decisions that were initially planed for Plan 9 and had to be thrown away due to implementation issues, like Alef then reborned as Limbo.
In any case the C APIs are the same as Plan 9 anyway.
