> One of the promises that lead me to buy one was the hackability - "It's Linux!" "You can SSH into it!", which, on paper (heh) is still true, but in practice very much isn't.

Can you expand on this a bit? Can't you still run third party software on the newer iterations?

Yes. The Paper Pro (and presumably the Move) require you to explicitly enable developer mode in order to enable ssh access where older devices had it enabled by default. USB still works. It is, however, not easy to toggle dev mode on and off - so once you activate it you will probably keep it active.