With plot holes big enough to pilot a space cruiser through, Geneshaft is, essentially, a very poor execution of a decent concept. The show relies on the premise that in the future, mankind relies solely on genetic engineering to reproduce; they produce nine women to every one male and have done away with the concept of love. Everyone has a special ability, so basically you have a planet full of badass women. Then this big ring comes in and everyone's afraid of it. Naturally it turns out to be swarming with aliens, so a team of cute girls is assembled to kick some butt. While the cute-girls-exterminating-alien-swarm idea has been done before, you'd be hard pressed to find another anime series that attempts to set their stage with the trappings of genetic engineering that are this harsh; ultimately, it's a failure. Not a burning wreckage, but still a failure.
Here's the big problem: if you breed humans in a lab and they don't need to reproduce the old fashioned way, what's the point of having gender at all? Why do the females have sex organs? (Why do they all have particularly pronounced sex organs?) Why not just make everyone a neuter? Why is the "perfect human" an ice queen with a flawless body and gigantic breasts? Since there's no love and people aren't judged based on physical appearance anymore, why does the "perfect human"'s only qualification for being perfect seem to be physical attractiveness? Wouldn't they be more likely to judge perfection based on ability and personality? The answer is simple: you can't sell an anime series without attractive characters, so they just sort of glossed over that one gigantic, problematic plot hole. Furthermore, if there's no love, then why do certain characters in the show seem to have a familial love for each other? None of this is ever really explained, and if you can't buy the very concept a show is based on, you aren't going to enjoy the series.
When you break it down to basics, Geneshaft's real problem is a lack of interesting or compelling characters and some fairly terrible dialogue scripting. The main character is, for the most part, intolerable. She has issues with her own ability and has an inferiority complex, but beyond that, she spends most of her time whining and being, in general, an unsympathetic annoyance. Her "big sister" character behaves in a forced, unconvincing fashion (witness their meeting in the first episode for an example of how totally awkward the writing in this show is. They're fighting, but they love each other! Yet there isn't supposed to be any love in this world!!). The other characters are mostly stock archetypes from other "girls in space" shows, including Little Annoying Brat Girl, Super Perfect Ice Queen, Subservient Girl in Glasses, that sort of thing. There's really nobody to like, which is a big problem.
The animation is serviceable but nothing impressive. The CG is understated in some scenes, and in others, about as awkward as a fourteen-year-old at her first Prom. Music-wise, the show is a surprise. It's mostly hard rock, which is uncommon for a sci-fi series. It may not necessarily fit the tone of the series, but it's pretty decent music. Geneshaft probably had a medium-sized budget, and they did a decent job with what they had.
The dub is a totally mixed bag, with many lows and not so many highs. The main character, voiced by Amanda Wynn-Lee (who usually does quality work), is a raspy disaster. She sounds absolutely terrible; the voice she's doing is not capable of delivering the lines properly. Switching to the Japanese track gives you an idea of what she's going for, but it's a failure. Hearing Paula Tiso (who did a smashing job with Lulu in Final Fantasy X) as Mir
Lotus, the perfect woman, is a treat. She does a good job, given that she doesn't have a whole lot to work with. The other voices are mostly generic, save for venerable fan favorite Crispin Freeman reprising his Alucard voice for Mario Musicanova. His bratty little counterpart, Tiki, is basically a higher-pitched version of the main character, and it's a total disaster. Jameson Price does a decent job as "Lord Sneak." (Who's that dapper swindler out of Tammany Hall? It's the Sneak!) But his talents are wasted on such a static character. Stick with the Japanese language version of this series, and do yourself a big favor.
Overall, it's not that Geneshaft is a terrible show; it just doesn't make a whole lot of sense. After the first episode the storyline seems to stall and dive into a tailspin. There's a ton of plot movement in the first episode, but after that, not a whole lot happens, and they wind up repeating what you already know a few times over. You'll spend half the time just trying to figure out all the plot holes. If they were trying to make a statement about gender politics (never mind the concept of a bunch of women having to use something called "The Shaft" to save the Earth; read that however you like), they failed--big time. If you want science fiction, watch Crest of the Stars. Geneshaft just isn't worth it.