It's an unpopular show in the West, mostly because of its subject matter. (That's why it became Funimation's first subtitle-only release, although it then sold quite well and they've since done other subtitle-only releases.) The title translates as "he's my big brother, but if there's love, that doesn't matter!" You can see how that might get a reaction, especially among fans who were unhappy about incest being used as a semi-mainstream romantic option in anime and manga. The puritan view on this would be "incest isn't clever and it isn't funny".
Well, the puritans are wrong. It can be very funny, as here.
It's also a harem comedy, which is another reason to be suspicious of it. Personally, though, I found it more palatable than much of the genre. The message of the stereotypical harem comedy is "all girls will fall in love with you, so you don't need to put any effort into finding a girlfriend because you'll be surrounded by gorgeous women because you're such a nice guy."
The message of this show is "BLOODY HELL, WHAT A BUNCH OF FREAKS". This is more plausible. The core girls are:
(a) Akiko, who's so infatuated with her brother Akito that she thinks her obsession is normal and has no shame in talking about it to her classmates. She's hysterical. Admittedly she's a fairly one-note character, with almost everything she says and does being Akito-related, but that's okay because she's hilarious. She's deranged and offensive, i.e. awesome.
(b) Anastasia, a deadpan sadist who talks abusively insane filth to mess with your head. She might be a bigger loon than Akiko.
(c) Arashi, an exhibitionist who'll shag anything that moves and sees the entire cast (male and female) as her targets.
(d) Ginbei, the normal one. Well, normal-ish. She's Akito's childhood friend and frets that he doesn't see her as feminine. (She uses masculine pronouns and has short hair and no boobs.)
Oh, and halfway through we meet Akito's twelve-year-old fiancee who also calls him "big brother".
It's targeting a family audience, then! No, just joking. It's as if someone was ticking off a list of how offensive you could be in an anime. Thinking about it, they probably were. There's also a "WHAT THE HELL" opening title sequence that's almost comedy porn. It's mesmerising. That said, though, the show's not technically crossing any lines, since nothing illegal ever happens. There's certainly no incest or paedophilia. No one even has sex. Arisa (the twelve-year-old) is completely safe throughout. You could almost call it family friendly, but in an aggressively filthy way.
I also liked the male protagonist, Akito, by the way. He doesn't do comedy reactions, which itself becomes funny. He won't take people's outrageous utterances seriously. He'll just listen calmly, reject everything they say and then get on with what he was doing. There's room for potential concern with him and Akiko, though, given his alarming choices with his part-time job and the fact that he's actually super-affectionate and demonstrative towards her. He often tells her he loves her and that she's the most important person in his life. It's just that he's only saying that in a brotherly way, while at the same time practically having to beat off Akiko with sticks.
I think the series falls off slightly towards the end. As often happens with harem anime, the show gets less interesting once it's settled into a status quo. Story points like Arashi's personality switch and Anastasia's no-knickers episode don't have a point and don't really go anywhere. (One might also wonder why Anastasia wore such a short skirt even after she'd lost her underwear, but I think that's solved by saying "she's Anastasia". If she can't even find her underwear in her own bedroom, then it's not implausible that she also can't find trousers or a more sensible skirt. Besides, she might not own those in the first place.)
Even given that, though, I still think the show's great. I certainly prefer it to what I've seen of superficially similar series like, say, Seitokai Yakuindomo, which gave me the impression of thinking that talking filth is so funny that a show doesn't need any other content. This, on the other hand, has a cast of explosively memorable whack jobs who'll say and do things that are genuinely outrageous. Even Ginbei's capable of making my jaw drop. Sometimes it's just silly. I'd recommend it to anyone who likes comedy and doesn't mind potentially offensive content.
"Incidentally, Akito, putting aside whether or not you're a paedophile..."