Story: There isn't much of one, outside from Ebichu the house-keeping hamster making observations about her owner's sex life and making dirty jokes. There is a constant of her master dealing with being unmarried and her boyfriend being a useless, cheating bum... and there is the guy that is in love with Ebichu... but it's not really a plot, just how the characters interact with each other.
The plot is mostly sex jokes. Lots and lots of sex jokes.
Animation: I can draw better than Ebichu's art style, to be perfectly honest. Anyone with the basic knowledge of human anatomy could. The animation is completely secondary, and doesn't have any of those really great "OH LOOK AT THAT" scenes a lot of anime do.
The best part of the animation is probably Ebichu's expressions, honestly.
Sound: The voice actors are okay, but most of the sound comes from Ebichu's little kid-esque voice and various sound effects, from moans to splurts to smacks. Not an episode goes by where you don't hear sex noises.
Characters: Ebichu is a bluntly honest hamster, who's somewhat innocent in that she just wants to help everyone and has that little kid mentality of not understanding why she shouldn't be saying what she's saying. Most of the other characters are realistic... her master who is frustrated with her station in life and is so desparate she keeps going back to the same loser... the loser who keeps cheating on his girlfriend with them skanky girls... the others only show up for a short amount of time, but most of the characer interaction comes from Ebichu pissing them off by saying something she shouldn't, insulting them in some way or talking about their sex life to other people.
Overall, if you like sex jokes and want to learn some Japanese slang for vaginas and testicles and sex-sounds, this show is what you want. If you want ecchi with a plot or hentai to fap to, this... isn't what you're looking for. It's only good as NSFW comedy, and that's if you don't get tired of the same pussy jokes over and over again.
It really gets into some of Japan's big societal problems, as well as problems we all have as people... feeling lonely, feeling like the universe is out to get us, needing something to blame, losing people...