While I can understand the 'effort' comment on the K4, anywhere else, it's pretty much: unzip, eject, press button. Voilą. (Remember: the JB on (most) Kindle is *one* single file sitting there being useful on your device

. Woohoo!).
That said, not going in blind is always a good thing, so let's agree that the effort lies in reading up on the various docs

.
@eschwartz: Going with CM means going with CM, there's not much we can do on that front, besides doing the work ourselves, which would mean handling the JSON & SQL ourselves, and then restarting the framework, and would also mean a permanent tiny daemon to detect changes

. So, err: nope ^^. [That said, there were a few tools that successfully did part of that, but mostly revolved around building collections based on the directory structure].
As for the other way around (Kindle -> Calibre), the incremental update support pretty much relies on not being run twice w/ the same dataset, which cannot be assured if done automatically on plug

. The fact that it would basically only save one click isn't terribly appealing either ^^