I'm sure most of you have seen a show which would have been breathtakingly bad, except every time you wanted to cringe, you also wanted to laugh. That's generally "so bad it's good" style, but sometimes, it shows the writer's genuine comedic talent.
This is what Absolute Boyfriend is. As a romcom, it's great, and ridiculous. As a deeper story-- and there are plenty of places for it to be one-- it stumbles.
Plot
The story is about a high school girl who really wants a boyfriend and can't get one. So, she orders a robot one online. He shows up to her door-- with a million dollar price tag attached!
The real plot of the story essentially follows their cohabitation. In order to not be in debt to the company forever, she needs to give this robot, who she calls 'Night', life experience and data on women; while that's essentially just a plot device to keep them together, it does keep interfering with their lives.
In addition to Riiko's other love interests and friends causing conflict, Night's a "born sexy yesterday" kind of character who needs help to stop from causing chaos. Honestly? I'm a guy, but it's very refreshing to see that trope with a male character instead of a female one.
Comedy
It's pretty absurdist, though it doesn't rely on that. Basically, the story runs at a rapid pace, with the protagonist Riiko especially creating chaos at every turn. The characters will say anything with no real sense of discretion. It's pretty great.
The creator openly just makes wild story decisions for gags, and it's a great ride if that's what you're looking for. Another upside is that, unlike other rom-coms, it never has the joke of the female lead beating up the male lead. (Or vice versa). Its jokes are more versatile than that, which makes it more enjoyable even if you don't mind that trope.
Characters
If you're writing a manga like Absolute Boyfriend, where the premise of one of the characters is that he's the perfect man, you have to nail making him lovable. Is Night lovable? For me, at least, the answer is a resounding yes.
In addition to being pretty handsome (I think) and genuinely gallant, he's also really cute and endearing in a puppy-dog like way. He's innocent, sweet, and will do anything for Riiko.
Honestly, by the end of the story, I got pretty concerned for him. He looks like a high school boy and has no life experience, but his job's basically to be a sex doll. Unfortunately, this story tends to hide from its serious implications, and that's never really explored.
The other characters aren't very good. Riiko, the protagonist, is refreshing because she's funny and never really sexualized, but she doesn't have anything special going for her and also doesn't deal with her situations very well. I didn't remember her name until a decent way through the manga, which should tell you something.
There's also Soshi, Riiko's childhood friend and Night's rival in love.
...I don't like him. Basically, he's meant to be a serious character, genuinely pining for Riiko. But the mangaka isn't great at writing serious stuff. at least not for this manga. Soshi mostly became, to me, an annoying guy without many gags-- maybe because I liked Night so much, and wanted him to get Riiko's love, but also, since Soshi didn't have a purpose outside that, I felt like any time we spent on him was kind of useless if he wasn't going to be the one who got with Riiko. Which, apparently the mangaka didn't decide until a long way through the story; but at the time, it felt like a foregone conclusion to me. He's not the naked guy on the cover and not the guy the main plot is about.
Other than that, there are 2 pretty forgettable girls (though the second one, with dark hair, does have her charms, she's not well written enough that I can even remember her name now); another guy who I won't go into too much for spoilers; Gaku, a genuinely fun character; and a little kid, who's Gaku's boss.
(Girl #2).Gaku's the marketing guy for the company who made Night: he dresses in cosplay all the time and has a great chaotic presence. Underneath it all, though, he's actually pretty normal, and he ended up being one of the characters I was rooting for most at the end; as he started to consider leaving his shady company.
Summary
I spent so long on the characters because characters tend to make or break a comedy (in this case, I think they make it) but also to avoid spoilers. There's a lot of exciting things that happen in this manga, but a lot of them feel pretty contrived. Whether you like it depends on whether you live for silly drama or not. Personally, I do; but even as a fan of love triangle plots, the love triangle specifically felt really weak.
Without the comedy, and just the existing drama, this would be a pretty bad story. (Luckily, there's comedy.)
Another weakness is that the creator doesn't really want to write a science fiction story, especially not a story about almost fully sentient/sapient sex robots; nor really a story about whether those robots ARE sentient or not; despite having set herself up to write all three. Night's implied to have broken out of his programming and to feel the full spectrum of emotions by the end, but his 'perfect' personality never really changes in response, and so it feels ambiguous; which isn't the feeling you really want looming when your main couple gets together. Plus, the story could have been much more interesting that way.
That said, I think anyone judging this manga should think of how common these stories are for male audiences. A lot of people will read this kind of fantasy with genders swapped and not question it, but then call this story silly and bad. Yeah, it's silly; both versions of these romances are silly! But both can also be good, entertaining, fun, and sweet, and I think this manga's pretty good in all of those regards.