Let's begin.
Neon Genesis Evangelion: the legendary mother of mecha genre, and probably one of the most discussed animes of all time. This anime divides opinions quite harshly; you either love it, or despise it with your whole heart. Neon Genesis Evangelion is not for everybody - yet I do recommend it for everyone, just so that you can form your own opinion of it. For me, Neon Genesis Evangelion was a solid 10, even though my theories of the whole series vary from extremely deep explanations, to utter confusion, as in: "I have no fucking idea what this whole anime was about".
So, what is so great about this anime?
Let's start with the plot; Neon Genesis Evangelion (or NGE shortly) tells the (confusing) story of 14-year-old Ikari Shinji, commonly known as "spineless coward" in reviews and on forums. Shinji Ikari fights with daddy issues, like every self-respecting anime protagonist does. In addition to having to fight with daddy issues, Shinji is chosen to pilot a massive-robot-like-mecha-humanoid-thing called EVA. Along with other 14-year-old kids, he fights against monsters that are ironically called 'Angels'.
Evangelion's plot isn't unique, we've seen all of this before: monsters fighting other monsters is nothing new. In the beginning of the anime, the story seems very simple and most of the episodes follow the same routine - characters interacting, monster (/angel) appears, there's a problem, the monster's destroyed. Only at the end of the series things are starting to get serious.
How the anime progresses, is what makes it so outstanding. The story progresses gradually, never actually giving you the whole story. Some of the questions are left unanswered, giving the viewer a chance to form their own theories and opinions based on the anime. Especially the ending leaves the viewer a lot of space to think. I've heard somebody say that 'everybody sees the story of Evangelion differently', and I think that is quite true.
One of the reasons why I liked this anime so much, was its characters. They appear very human-like, realistic, and you can easily identify yourself with them. Every single character has their own vulnerabilities, and as the story progresses, their backstories are revealed. Evangelion's characters have a lot of depth in them. During the last two episodes, we even get to see what's going on inside their minds, as the story switches from the outer world to inside of the minds of the main characters.
Neon Genesis Evangelion had many good characters, but the ones that stood out to me the most were Shinji's cold father Ikari Gendo, the egotistical Asuka Langley Soryu and Nagisa Kaworu. I especially liked Nagisa Kaworu, who seemed to have a great impact on Shinji, even though he only appeared in one episode. In a matter of minutes, he helped Shinji change from an insecure 'emo kid' to a blushing, smiling boy. I would've loved to see more of these together, but... yeah.
The art style of NGE is really good, considering the fact that it's almost 20 years old. The designs of the EVAs are really well made, as are the character designs. The battle scenes are also nice to watch. Everything about the art is good if you just don't mind the usage of the stills, especially at the end of the series. This however, is understandable when you take in consideration the fact that they were having difficulties with budget. The lack of budget really shows in the last episodes of the series, yet they've tried hiding it with really creative ways.
I don't have anything bad to say about the sound, neither. I'd just like to give an honorable mention to the opening song, "Cruel Angel's Thesis" (/Zankokuna Tenshi no These) by Takahashi Yoko. This is by far one of my favorite opening songs in the whole anime history. A great song you'll never grow tired of (...that might be just me though).
All in all, Neon Genesis Evangelion is an anime worth watching. Hate it or love it, you can't deny the fact that it is one of the most legendary animes that shaped what the anime industry is nowadays. Watching Neon Genesis Evangelion is an adventure you shouldn't miss.
