I first heard of Kareshi Kanojo no Jijoo when I was looking at Gainax's website after watching the Neon Genesis Evangelion series. It was their next big project after Neon Genesis and after being blown away with that series, I had to see about this next one.
I instantly fell in love with the series, watching it completely through until its sad first and last season run. I felt a bit empty after watching the series and ending with too many open ends. The manga cheered me up, though, buying every tankoubon of the series for only 3 bucks a piece.
There are summaries about the series already, so let me just make my statement on why I fell in love with the series.
It didn't base itself off of the never-obtaining-love plots that saturate American TV shows, such as Gilmore Girls, Friends, Good Morning, Miami, etc. The show gives wonderful depth as to first loves and how relationships build, rather than collapse, like most shows.
My fiance and I enjoyed sitting down and watching this series together because of its honesty and cuteness. Watching the warmth of a first kiss, the first time one holds hands... its very endearing.
I would recommend this to those Shoujo lovers out there, but I would say stay away to fanboys.