These seinen titles feature characters that begin dating early on. The main cast from each series act differently than the other, but the series none the less gives off a similar atmosphere due to the way the characters act around one another. Ultimately, the most similar thing about these two manga are the simple yet sweet relationships between the main couple.
Here to second the opinion to read this. Both are pretty fantastic. Similar story lines but Kyou is more comedic I felt while Fuji was a bit more dramatic. Don't get me wrong both have heavier moments and heart strings scenes.
Very enjoyable, highly recommend both.