To start off this review, I will give three general reasons as to why this series is awesome:
The story, in my opinion is pretty good. Ika Musume decides humanity sucks, and that she is going to conquer it. That plan falls flat on it's ass, due to her breaking the wall of the first building she encounters, and she is forced to work at a beach house restaurant to repay the debt. This device has been used before in several series, but this series has the charm of having a character completely ignorant of everything in the human world introduced to her, which makes good reading. The humor of the series is great, making me, a person who usually sticks to high brow humor, laugh my ass off at predictable events, at creepy jokes, hilarious situations, and even a few sex jokes. And these sex jokes do involve tentacles.
The art is great. No complaints, and nothing really to elaborate about it.
As stated at the beginning, the main character is a squid-human. A cephalopod-person. That in itself is awesome and funny, because we all know that cephalopods are amazing beings. They are just too cool for school. The other characters in this series are not squid-humans, just regular humans, but despite their handicaps of not being squids, they are awesome as well. You get the only sane person, Eiko, who constantly chastises Ika. You get her sister, Chizuru, the soft-spoken cute one, who is actually strong and scary. You get her brother, Takeru, who...really isn't anything special. You get the manly man, Goro, who is actually kind of creepy. And finally, you get Sanae, the friend who cannot stop being a pervert, the one who constantly dresses Ika up and takes pictures. All the characters fit the molds of the usual layout, which isn't a bad thing.
Overall, this series is definitely worth a read. Great humor, good story, a series that can be casually read. I would suggest reading this series after reading something very serious or dark, as this will cheer you up immensely. Word of warning though, do not look up images of the characters. The internet is a dark place, and especially so if anything remotely related to tentacles is involved.