I have a mini. I understand there are people who don't like it much because it has little features and all that.
However I think it is an ideal Tamagotchi for when you have tons of homework or work, and your time is reduced. They don't request much care, and they are used more as a "fashion accessory".
What Mini's do (and don't do):
> They don't have icons. You can only interact with it when it needs something. They have hard-to-see pixels, but it is fun to catch them doing silly animations.
> The time doesn't have seconds
> No games
> You can cure illness, feed, clean poo and turn lights off with one button
The evolution is:
Egg > Marutchi > 1st adult > 2nd adult
(Some adults englobe Mametchi, Kuchipatchi, Furawatchi, Ginjirotchi, Ojayitchi, Maskutchi (P1 version) and some others).
The Japanese version also has Unchi-kun (the "Lucky" poo) if you ignore it a lot. Marutchi stage lasts 1 day, and each adult about 5-7 days, I cannot remember, but it was a long time.
The good thing about minis is their low battery "requirances", so when one of your other Tamagotchis runs out of battery, you can put it in your Mini and it will last a "Mini-life or two".