After reading synopsis you can probably tell that Aizawa-san Zoushoku is not typical harem. Personally I wouldn't call it harem at all, as most of the cast are Aizawas that don't act like usual harem members.
Story of this manga is very nice. It introduces the multiplying mechanic in the very beginning and is focused on it until the end. Other than that it's mostly normal high school romance.
Aizawa-san Zoushoku is very lighthearted and has many cute moments. Comedy will make you smile but isn't that great in my opinion. Romance progresses nicely and is very satisfying.
One thing that surprised me are characters. Aizawa herself is
very interesting and unusual main heroine. Souta seems like usual "nice guy" type of character but doesn't fall into "harem MC" stereotype. Other characters were also nice, although I think they should have had more development.
Art was ok. It wasn't too detailed and backgrounds weren't really noticable, but such simplicity seems acceptable for this kind of manga. On the other hand characters design was nice and their expressions were really good.
I just wish we got some fanservice with all the Aizawas...
Overall Aizawa-san Zoushoku is enjoyable, rather short (20 pages per chapter) and lighthearted story. It might not be great but I don't think anyone could really dislike this manga.