Much like Fae I had a Pocket Pikachu (2) when I was younger; I bought it way back when it was first released and I was on holiday in the US. I remember it not doing a whole lot and Pikachu spent most of his/her time hating my very existence (I was only ten at the time and apparently did not walk enough to earn enough watts to keep them happy). When I was a bit older I loaned it to a friend who was mad about Pokemon and she accidentally flushed it. Anyway, I replaced it last month, mostly for nostalgia reasons. As I remembered, it really doesn't do a great deal, but if you just want a pedometer with some cute animations, it's perfect. I actually really love the simplicity of it (there's no care involved; you just earn watts for walking or playing the game and give them to Pikachu) as it means I can take it anywhere and don't ever need to put it on pause. However, if you're wanting a bit more than cute animations attached to a pedometer, I would not recommend this (it's also relatively expensive).
I have also recently aquired a Cocotama, which is insanely cute. Like PP2 it doesn't really have a 'care' element, but it is actually quite involved. You unlock items (such as food and toys) with X amount of steps. You can also unlock new games, rooms and furniture (to decorate the rooms with), as well as new Cocotamas (although only two are 'playable'). There are six games to unlock in total, which I have managed to do over a weekend. There does appear to be loads of content on the Cocotama. You can also level up the two 'playable' characters, which also unlocks toys. I am enjoying it immensely, especially as the lack of any real care element makes it much more casual 'pet'. (I use my PP2 to keep track of my steps and cheat with the Cocotama by shaking it).
That said, I do feel like I'm missing out on quite a bit of content by having (very) limited Japanese. There's a lot of cutscenes with long conversations between the different characters, and I can't read much more than 'good morning' and 'good night'. I do think it's a shame as I feel like I am missing out (more so than when I use a Japanese language Tamagotchi, as the conversations are usually just unnecessary, but fun, babble; at least, if my iD LE/patched P's is anything to go by). However, it is cute and I'm enjoying unlocking various things and I definitely do not regret buying it (just maybe regret getting the pink version).
Hope this helps!