It's entertaining enough, but it's a bit of a mess. Is it a comedy? Is it a harem fanservice romp? Is it dramatic? The answer to all of those questions is "yes" and "no". I wouldn't really recommend this show, since there's better out there in all those departments, but it's perfectly watchable.
It started out as an adult video game, by the way. Sorry, "visual novel". Apparently the game's much more serious and dramatic. All the girls have trauma and psychological issues that the protagonist (Ren) will help them overcome. The anime, though, is lighthearted and oddly innocent in its filth, if you don't mind some nudity and fetish fuel. And incestuous lesbian sexual harassment. And multiple masochists. And panty shots. And sexy nurses. And a closing credits sequence that's just an excuse to parade the female cast in their underwear. Even given all that, though, I didn't think it felt particularly exploitative and indeed didn't even feel like a harem anime.
There's a harem formula, you see. Girls live with a milquetoast hero and compete for his affections. Who will he choose? (Answer: none of them, because choosing would pop the genre bubble.) You see, harem shows are built around romance. It's pandering, unhealthy fantasy for otaku that presupposes an endless supply of unconditional worship, but nonetheless romance.
Here, though, we have:
(a) a hero (Ren) with clear motivations and a crisply defined relationship with the rest of the cast. He's a butler. He wants to be a good butler. No one's in love with him, because he's the butler. They like him and they tease him, but there's absolutely no chance of anyone treating him as anything but the dogsbody.
(b) he's in a chaste but intense relationship with his sister, Mihato. Admittedly Ren's not blind to other girls and there's no evidence that his feelings aren't fraternal, but Mihato isn't far off being a scary stalker. Not only is she besotted in an inappropriate way, but she doesn't bother to hide this and thinks nothing of telling strangers that she's got a brother complex. (Apparently this can be taken further in the visual novel.) Given their circumstances, though, it's almost understandable. They've escaped from an abusive home. Their mother's dead and their father's a violent drunkard. Ren and Mihato are alone together, with the mutual priority of protecting and supporting each other. They're actually quite sweet, if you can cope with the sibling boundaries thing. Having started out in ep.1 as homeless runaways, their jobs in the Kuonji household are a massive deal for them. If one were to get fired, though, the other would immediately quit too and follow them.
The dramatic significance of all this is that being a butler outweighs almost everything else for Ren. Girls taking off their clothes are inconvenient. Life would be so much easier if everyone just behaved normally.
(c) Fanservice scenes thus don't play as you'd expect. If Ren walks in on one of his mistresses getting changed, his job is simply not to bat an eyelid and get on with his working day. Nudity has nothing to do with honest sex and everything to do with the house being full of weirdos. Shinra is cold, arrogant and gets her jollies by "teasing" people. Her definition of this involves repeatedly near-raping her sister (played entirely for comedy), molesting her maids and occasionally trying to wind up Ren. If the other person isn't annoyed or frustrated, Shinra gets bored and stops. Similarly Miyu is an exhibitionist... but she also looks about twelve (to her frustration) and one could theorise at some length about what's going through her head.
The household staff basically ignore all this. The show doesn't have that much nudity anyway, to be honest, and even the audience soon learns to do as the staff do and pay it no attention. Even when Ren goes on a date with Shinra in ep.12, it's anti-romantic and an exercise in life advice and master-servant relationships. Miyu likes sleeping with her servants, but only in the literal sense. They sleep. That's all. It's almost parental. We thus have anti-fanservice fanservice and a harem show that somehow isn't.
Is it a comedy, then? Is it a drama? Umm... well, you're probably better off thinking of it as neither. It's certainly lighthearted and over-the-top, but it's not consistently funny. (I laughed at no one believing Haru's love confession in ep.11, though.) Sometimes it'll take the characters seriously and do a dramatic episode with tragic backstory... but the first such episode was ep.5 and until then I'd been watching fluff.
The characters are quite fun, although I'm surprised that not one but two cast members have self-esteem issues due to being uninteresting people. (That's their characterisation: The Normal One Who Nobody Notices.) Benisu is obnoxious, but her past makes her sympathetic. Natose is the kindest cast member, although she's also an eyepatch-wearing commando. Shinra is definitely memorable. Ageha's masochistic butler Kojuuro is very funny. However the most attention-grabbing character is clearly Mihato, even though she's relatively underused and is mostly just one of the supporting cast. Mihato has three modes:
1. NURTURING AND MOTHERLY, i.e. default mode. This Mihato talks in a dreamy, angelic voice, is nice to everyone and is basically adorable. She's basically a forgiving, generous person, so she'll stay in this mode even when you might be waiting for her to get jealous.
2. GETTING A BIT SCARY NOW. If something stressful is happening (i.e. a threat to her relationship with Ren), you might find that Mihato happens to be holding a bloody kitchen knife or something. There's a perfectly innocent explanation. She's cutting up the fish for dinner. What makes it scarier, though, is that she seems unaware that anything's wrong and goes on talking in Nurturing and Motherly mode.
3. GREEN FACE, i.e. yandere. This Mihato is pissed off and wants you to know about it. Her voice changes. Her face darkens. If you've done something particularly foolish, e.g. beating up Ren, then she might push a spike into your neck with a squishy sound and then go on pushing it deeper.
The latter's in ep.5, by the way. I'm still not sure what happened there. This is the kind of lightweight, good-natured show where you don't expect anyone to die... but what our heroes do to those Ren-beaters does look kind of fatal. Then the episode continues and we never see or hear from them again.
The show has some nice touches, I think, underneath the silliness. I liked its use of non-verbal storytelling. You'll have dialogue being undercut by animation and body language, so you won't get what the scene's about if you're just reading the subtitles.
I don't really think the show works. It's quite fun, but it's three shows in one without completely succeeding at any of them. It also doesn't have a firm grip on its sprawling cast. The drama works better than you'd think, but the show's not really going for it and half the cast are never anything but comic relief. I'd have liked more Natose, for a start. I'm sure the visual novel would have been more satisfying (and there's an all-ages Playstation version if you're not into pornographic computer games). However it's not offensive (despite what you might guess from some of its content), and it does have more depth than most ecchi shows. The characterisation works. It's an entertaining show that won't make you feel soiled. I even quite like its quirks, which make it distinctive. Not worth a purchase, but perhaps a rental.