On the V3 the Toddlers and Teens seem care-related, but the Adults I can't yet tell. I've gotten 3 Leaftchi in a row(I screamed the 3rd time.), so it's probably care related, but it must be alot more sensitive to care because of all the possibilites.
Oh, and on the Toddlers, I'm pretty sure the order of worst to best is--
Kuchimatchi(Or something like that), Tamatchi, The one that looks Marutchi with a big line on it's head, and Mizumatchi as the best.
ooh, i thought tama's was suppose to have character variation for example:
first gen best character: Mametchi
second gen best character: Mimitchi
well, I maybe wrong, 'cos my friend got tarakotchi for 2 generations