Like others have noted this is a very straightforward story. It is all about the two main characters. Side characters are there mostly supporting for the leads. If you are looking for a more complex story this is not it.
If you want something sugary sweet and just overall a fun time. I say pick this up. I read all 13 volumes in a day. It is quick-paced enough to do so since there are no slow periods in the storyline.
Overall, I am happy I read this series and will read it again in the future since it is a fun read.