Better than Bokuben in terms of tutor-student relationship and study together. One of the best Harem I've ever read.
I rarely read shounen harem because most of them have boring plots, many dull fanservices with weak execution, there is nothing else except for fun. I'm a bit subjective in this matter, even though I'm a girl I don't like reverse-harem too. But don't worry, I'm here to give what makes this series worth reading from many harems out there. As subjective as possible without expressing hatred.
5-toubun no Hanayome presents a unique concept, this is the key why this series is very exciting to follow. Even though the author gives many 'past cuts' and signals 'what will happen in the future', it still makes the reader hope and curious. It might be predictable, but it's uncertain because of the identical resemblance, whether any changes can occur with many events that have passed from spending time together.
The fanservices aren't disgusting at all. It didn't happen frequently to make random jokes. The issues raised are also quite sensitive, there are changes to the twins' process, starting from the little things they really want, do and dream about. But that doesn't mean that this series is completely different, the twins also open in a certain period even though the process is not instant.
I like the approach to getting to know each other's characters, I'm quite observant and sensitive, but none of them makes me upset with their behavior. They are surprisingly normal. And if there are conflicts between them, they try to solve it. The concept of twins is good rather than hostile to one another, no matter how different their personalities are, unity is the most important. There is a warm impression that is fun to see.
So far I have chosen Itsuki, she is stubborn (tsundere type), but she is one of the most rational thinking and mature after Ichika. Then there is Yotsuba, she is sweet, her jovial personality is always interesting to see.
And the last thing, most harems usually get their share to get a certain moment, but this is not, is quite one-sided. Also don't forget to mention about the stunning 2-page panel, it's really great.