Realistic ecchi from a woman's point of view.
Momoiro Sisters' animation is not the best out there. Easy animation, not too detailed and primarily focused on the comedy, they don't pay too much attention to the details. Still, although the only available fansubs are of poor quality, the animation isn't that bad at all and it does fit the style of the series.
There are no reused frames and they don't have recaps, which makes this series a nice watch at least.
The voiceactors might sound a bit odd or poorly casted at first, but they are actually pretty well cast and they do a good job on the characters as soon as you've watched a few episodes and learn to appreciate the characters.
The SFX are done nicely, in a comical way, but the OP (note that AC stripped the OP from the first 7 or so episodes) is pretty addictive. Margaret is nice, fast and pretty well done, with even fitting lyrics for the series itself - if you bother reading them while humming along.
The story is not much of a story, but instead are mainly focused on the comedy part of the two sisters living in the same house. This results in a bunch of episodes from the point of view from both sisters of different age; the main characters. Momoko does it from her highschool (16) point of view, which is mostly about her ideas/problems with the first time, boyfriends, kissing and shaving 'down there', while onee-san Sakura (20-something) as an office-lady is working hard on problems like dieting, regular sex, babies, relationships with colleagues and marriage.
The fun part here is that both Sakura and Momoko are both realistic in terms of being woman themselves and their (im)mature desire for sex and talks about issues which men usually can't even imagine, but they're also the stereotype of women where even men can laugh about, giving this series a nice audience.
Don't expect a story on itself; all episodes are mostly standalones in which they tackle a certain problem where either Sakura or Momoko is coping with. But there are also issues which play over several episodes, not as a main focus, but rather as a sidefocus. And there are just silly episodes, like the jungle-episode, in which nothing makes sense except for the silly verbal ecchiness.
Momoiro Sisters doesn't lower itself to the point where they become hentai in animation - actually, they don't even come close to it, but the main focus of Momoiro Sisters is the verbal comedy. So don't expect any ecchi or hentai scenes; instead, expect some ecchi and very daring conversations or talks about stuff where we usually don't talk about - or only in very selective groups.
While Momoko is the rather innocent, but interested type of girl, her sister is the adult version of her. This results often in teasing over and over about Momoko being a virgin and Sakura not being able to get a steady boyfriend or husband. But both of them do have a fun personality to watch and also the other characters, although flat, are fun to have around. Don't expect much development, but instead watch them for their specific characteristics to make this show fun.
The value isn't much after the first time, but it's still possible to enjoy it - even though you already know all the jokes. Especially with company laughing out loud this series becomes pretty fun again.
I have to admit that the first time I didn't like the humor that much, so I discarded it pretty early on. But after getting into a mood where I could appreciate it more, I also realized that this series was very fun to watch - if you're in the right mood.