@Tiffanys, It would be nice if you said something extensive. From your forum posts, I think you've been watching a lot of shoujo-ai/yuri. Your opinion should be interesting. But I mean that for everyone, too. The discussion is more fun and interesting when people are thoughtful as to why they like/dislike, agree/disagree.
I mostly agree with the review, though I think it's overly critical in places. When watching something like Mnemosyne you have to understand that the sexual content is part of the base level. The sexy scenes are mostly unnecessary, but they aren't gratuitous or tactless. There's more purpose in it than just titillating the audience- it is pertinent to the story and characters.
In context, I imagine Mnemosyne stands up pretty well against other works in its genre. Context is crucial. Of course it's going to look oversexed compared to general anime, where most couples need twenty-some episodes to even realize their feelings, which maybe climaxes in a handhold and fade to black.
Also, I'd have my misgivings about any reviewer who says the writing is just "the screenwriters showing off just how “adult” they can be." That line itself screams deficiencies in the reviewer. Shows his conception of anime writing is terribly limited.
Rin: Daughter of Mnemosyne does a lot of things very well on a conceptual level. For instance, the time jumps from episode to episode were very convincing. The recent past felt like it, not just like the present with cellphones removed. The future wasn't just convincing, it was compelling and exciting with new technologies. The three Reality levels and the internet catastrophe (which is only hinted at; very skillful scene writing there) is enough material to warrant its own 26-episode series.
The sex/gore is only going to seem excessive if you haven't seen something more-so. Mnemosyne walks a very fine line, and does it with skill and utmost consciousness. On the spectrum, I don't think there is much shock value so I don't see what people make a fuss over. (Save Rin's piercing/bondage scene, but I think that served an overall purpose as well, and it didn't feel purely gratuitous/pornographic.)
The characters aren't bad, the story line isn't wholly predictable. That goes a pretty long way considering how much trash is out there, and how much trash we've all sat through.
Quickly, going back to the review:
Overall : B-
Overall (sub) : B-
Story : C
Animation : A
Art : A
Music : C
I liked the Japanese voice acting, but I imagine most of what I liked was just Mamiko Noto. It's hard not to be familiar with her voice- I think it's even more difficult to dislike. Animation/Art, I don't think belong in the A range because most of the animation is pretty flat and simple compared to animation-heavy works. The animation is good, but maybe only B level. Music, wanted to kill myself every time the intro played :P . Story I think deserves a B-, for all the stuff I said above. Overall a B.
Mnemosyne is what it is, and it isn't bad by any means. It's definitely far from laughably bad.