most people like mametchi for being a cute, adorable tamagotchi. He is very smart and needs perfect care to get on your v4, which everyone thinks is real fun. Mametchi is the tamagotchi mascot and he won tama island causing new to tamagotchi v4 owners to go crazy.
Mametchi is just the main character or the "mascot" as Mametchi 4ever said. Most people like him as their favorite character, but there are plenty of people who like other Tamagotchis better. <_< Mametchi is my personal favorite character, but they're all so cute; I love them all!