space are higher capacity and iirc a little more expensive. Bambino has an all-white (bianco) like abu (simple) but the rest of their lineup is the same diaper with a different print on the tape panel only. The bellisimo offers increased capacity though is otherwise identical except again for the tape panel art.
ABU has several varieties of the same model, but then offers several additional models such as Preschool, so there's more variety there.
Given the number of choices on both sides of the fence, it's hard to say just one way or the other. I personally like bambino's Teddy print the best, wear ABU's simple (plastic) during the day (daily) and their simple (or space, as I have some left) are an occasional overnight for when I expect a lot of wetting.
For lower volume nights, and regular at-home wear, it's quite a mix of other brands, which includes the teddy and some leftover bianco.
tl;dr: I prefer both, for different reasons, and also wear other types