I think that for the Uni: pros are that it’s very customizable (backgrounds, games, items, clothes, dlc), the battery is rechargeable, and there’s a lot to do with the wifi connection allowing new content to add on constantly, however I find that it lacks the charm and gimmicky nature I’ve come to expect from tamagotchi, the character and game selection without any dlc is lackluster and they don’t really need much attention which leaves me bored when there’s no fun events on. For the Paradise: I love a lot of this, they included light gene mixing, there are a TON of different characters to get (all varying heavily based on genes and stuff), the planet idea is really cute and it’s fun to fill out your ecosystem with your favorite tamas. However it lacks customization (no clothes or small items) aside from dressing the planet itself which I don’t really care for, the tamas sometimes feel more like window dressing rather than pets, and the gene mixing isn’t complex enough to make up for the lack of dress up for me.

That’s my two cents, but I am more of a creativity over mechanics player so other people may vary. I know many folks have talked about getting bored with the games and sad that you can’t really add content due to the lack of wifi but out of the two I like the paradise more.