Yotsuba to!, Usagi Drop Recommendations
Both are stories about a single dad raising an adorable little girl. Both have elements of innocence and wonder, and both are sweet and funny. I think Yotsuba&! is more funny than Usagi Drop, but Usagi Drop is better at portraying the realities of daily life with a young child.
Before Chapter 25, there are quite a few similarities between Usagi Drop and Yotsuba&! - namely, the fact that both of these mangas feature a grown man raising a child on their own. Even then, their approaches do have some important differences, namely the fact that Yotsuba&! is primarily told from the perspective of the child whilst Usagi Drop is told from the perspective of the parent.
I like to think of Yotsuba&! as a shining example of a "feel-good" read in that this is the kind of manga you'll want to pick up if you're feeling down and you need a mood booster.
Both are laid-back manga with relatively young male characters trying to raise little girls. While Yotsubato! is told more from the child's (Yotsuba's) point of view, Usagi Drop is told more from the dad's (Daikichi's) point of view.
Usagi Drop probably has a more calm feel than Yotsubato!, and is a touch more dramatic. But it's still very cute with a nice art style.
(Warning: If you read Usagi Drop, stop after volume 7. Yes, that's not very long, but trust me, the plot starts to go downhill in volume 8.)