It's a really comforting read, and despite being a slice, still features quite a bit of subtle character development for the protagonists. Beyond the flashy hijinks on the foreground, it deals seriously with sibling relationships, struggling with introversion and trying to fit in, teens searching for their way in life. And it's great at portraying warm familiar feelings.
All in all, a 10 out of 10 from me, and I strongly wonder at the low overall rating. If you're reading the comments deciding whether to read this manga, do yourself a favour and try half a dozen chapters.