It's hard to explain why I like this other than it's shameless fun. The characters feel very real and if you dislike Yotsuba you probably aren't human. The focus is (as you may have guessed) on Yotsuba and how she explores and learns about her knew environment, a small town, which she and her dad have recently moved to. Chapters are frequently set just after the other ends (be it a few hours or a few days) so since it began in 2005 with the start of the summer holidays we have only just reached autumn/winter of the same year.
The art is pretty simple but has been getting more and more detailed as it goes on and Azuma, the writer, has a great eye for facial expressions.
There are currently 53 chapters released most of which have been collected into 7 volumes with 8 two months from being filled. 6 of these have been released by ADV for you to go and buy. Scanlations can be found fairly easily if you're google savy so there is no reason not to give this a try.