Multiple systems are correct about their experiences. In particular, killing a N-person system is as bad as killing N singlets. (90%)
I'd say I'm reasonably confident that there is something interesting going on, but I wouldn't go as far as to say they are genuinely different people to the extent of having equal moral weight to standard human personalities.
I would guess they are closer to different patterns of accessing the same mental resources than fully different. (You could make an analogy with operating systems/programmes/user interfaces on a computer.)
I was very interested in the discussions and opinions that grew out of the last time this was played, but find digging through 800+ comments for a new game to start on the same thread annoying. I also don't want this game ruined by a potential sock puppet (whom ever it may be). So here's a non-sockpuppetiered Irrationality Game, if there's still interest. If there isn't, downvote to oblivion!
The original rules:
Enjoy!