Much earlier this year, I wrote a review on Elfen Lied but I didn't like the result so I scrapped it. My opinion was forced and I left out a lot of techanical details.
Elfen Lied was an anime that was glorified by anime fans everywhere, many of those who rate it as one of the best anime ever made, rating above true masterpieces such as Cowboy Bebop even. After hearing those ludicrous acclaims, I watched the show for my self and put aside what everyone else says about it.
The story in Elfen Lied isn't really much brag about, it tries desperately hard at being a deep, thought-provoking series but it just falls flat on solid concrete floor. The theme of "Exploring human nature and what horrible things they do" doesn't really have a coherent focus throughout the story, it's just an excuse for guts, gore,& other cheap dramatic effects to blanket the lackluster plot. Because of that many plot threads that really could have been explored were quickly abandoned, for example, the verbal and sexual abuse Mayu has taken from her biological mother and stepdad could have had more exploration. Would it have been nice if we were to know where the abuse roots from and to be able to examine how it matches with Mayu's characterization and actions but no the writers were far more focused on moving along the plot so they abandoned it in the same episode(ep no.5) it was introduced, then they basically act as though it never happened. It also doesn't help that it was an unneccessery thread to open up in the first place. A lot of the problems in the story attribute to Elfen Lied's incredibly short length, the story would have been better handled if it were atleast 26 episodes rather than 13 episodes but Elfen Lied was a dud in Japan so it couldn't happen.
While the production value and framerate is high, those aspects aren't everything to animation. There must be personality behind it all and that's something Elfen Lied lacks in the field of animation. Aside from certain scenes that are trying to convey a mood where it looks unique and really well put together, the general animation is flat and looks pretty standard. Also the gory scenes look ridiculous.
This is probably the best aspect to Elfen Lied. Hate Elfen Lied or not, there's no denying the excellent sound quality. The handling of the SFX and musical score fits with the general tone of the story absolutely to a "T". The sad scenes in Elfen Lied admittedly gave me chills and it might even bring others into an emotional drive however the voice-acting in both dub and the original sound really shakey and they overdo it in the dramatic scenes which can drag those scenes down for the more critical of people. Other than that, the sound is excellent, that is, if you're willing to look past the exceptionally poor voice-acting.
The characterization I say is without a doubt, Elfen Lied's weakest aspect. A lot of characters don't really contribute in the slightest to the plot(Yuka, Mayu) and most who actually contribute just simply fail to deliever what makes a good character(Bando, Kurama). Their tragic backstories and personal desires felt randomly brought together because the writers don't even bother bringing enough proper characterization to build upon. A perfect example would have to be Yuka, the strong feelings she holds for her cousin Kouta never really seemed apparent or built upon, they just randomly established it and they pretty much beat you over the head with it by turning her into an unlikable cunt. To establish a character's backstory or desires, it has to match with the characters previous characterization and actions in order to make them believable. The only character I truly liked was Lucy because her backstory and desires didn't feel so forced, plus she actually had some depth to her character unlike majority of the cast. Nyu could bite on a bunch of wires and get electricuted for all I care, she was just a Chi ripoff. The characters also seem to do unrealistic things like at the final episode, Kouta chose to forgive Lucy for what she did in the past. That was highly improbable. If I were Kouta, I wouldn't forgive her because she killed off his family(among hundreds of other innocent people) all in a fit of jealousy. She has no real excuse for killing all those people yet he forgives her?
With all that said I don't really hate Elfen Lied but it has several major flaws so I simply just can't join the banwagon and praise it. I do understand why it's popular though and it's for stuff like the forementioned excellence in sound quality.
Do I recommend it? If you enjoy stuff like Genocyber or Higurashi no Naku Koro ni, yes. Otherwise, there's much better stuff out there to watch.