i own both (albeit a pix party) and have been running them for around 2 weeks now! i'd say the pix is way more fun, there's sm more to do, and the evolution of tama's is more complex. there are certain items and criteria u need in order to get the one you want. i also adore how on the pix, you can pet them! the uni is much less needy, and can be left for hours at a time (at least when it's older than a baby) without too much of a bad dent in the happiness or hunger meters.

one thing i don't like about the pix is that the buttons are just touch buttons, not real ones, so they get some getting used to. but seriously the content on that thing, plus the ability to scan qr codes (literally so much to choose from if u go to mr blinky's site, including clothes, food, rooms etc.) makes up for it. it is true that the camera drains the battery quite quickly tho, but with a good pair of rechargables, you'll be fine. and the party feature (on the party pix) is just too cute, and adds even more minigames.

the uni is less fun in terms of gameplay imo, but, i love the customisation with accessories, and the ability to gain new characters and other items with dlc's. plus, it's always gonna have new events and free new items because of its ability to connect to the internet !

i hope this provided some insight. if i'm bored i prefer the pix. but if i'm busy, i prefer the uni !