pre scriptum: I put a short summary in the end if you don't want to read this.
No spoilers (I was careful
)
Sword Art Online (SAO) starts of nicely, it only depends on if you want a quick'n'go anime where you see lots of action or more of a slow-paced anime. The "intro" where it shows the character, develop their personality is a good 3-4 episodes. It sets up the ground in the next episodes and starts kicking in afterwards.
Currently, the anime has 25 episodes (2 seasons), It will have 2 more seasons at some undetermined date(hopefully)(Total of 4 seasons). There is a whole backstory to this anime if you're interested, but the anime progression is based off a novel. Therefore, there is some more development to the story than most other animes.
The part where peoples usually go "What the **** is going on" is... once they realize the pace at which the story goes. While most animes will follow the main character day-by-day, SAO jumps from event to event and only takes what it needs. So although there is 100 floors, you will see jumps of numerous floors (you can guess it since it's only 25 episodes for 2 seasons). This might lead to some miss comprehensions if you didn't follow the story closely or if you can't follow this kind of pattern. Though, if you watch the anime without doing something else (seen peoples playing video games at the same time or such) you should be able to follow easily and have a pleasant time.
Animes I would say are similar would be the Accel World and .Hack
Now, they are only similar in context (live video game kinda)(Accel World is by the same author though).
Overall, I think you should give it a try, it's special in it's way of going through the story and goes towards an underdeveloped topic. I consider it like Death Note and such in the way that, you have to try it. You might like it, you might not, but it will DEFINNETLY not be a waste of time to give it a try.
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SHORT SUMMARY
Story is good and original, it does have similarities with .Hack .
Characters are well developed.
The art is good, especially fighting scenes and "In-video-game" scenes, but I wouldn't place it in any special category.
Should you give it a try? Yes.
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-Jawarisin
PS: If you want more information or if I havn't been clear ennough on some points, feel free to ask, I will add anything needed for you to make a better choice
PS2: I could be more precise as in the "should you watch it" if you'd tell me animes you watched and liked, a few you disliked and what you usually look for in an anime