I love Sword Art Online, but I have more fun watching SAO: Abridged than the original. Many people who enjoy this the fan-made version of of the story (made by SWE team) think it is better than the original. I don't think so necessarily, as the original has a stronger "mood* and a charm that can't be explained, but for a parody series, it's very impressive!
It depends on taste, and while I do enjoy Abridged more than the original, the humor might not suit everyone and I like the original better in some parts as Abridged's comedy downplays some of the serious moments.
Each episode of Abridged is full of references anc call-backs, which makes it feel it has a better continuity than the original SAO.
The biggest difference in SAO Abridged is the personality of the characters. Most characters in the abridged versions act like jerks, but also in a way that you expect normal (but entitled) MMO players from real life to act. The protagonists however take this to the extreme! Abridged Kirito and Asuna are "less people than a loose collection of character defects" as one character politely points one time. The best thing that it's played both realistically and humorously in balance that you can't help but have empathy to all the characters. (Who aren't NPCs.)
Spoilers for Both Versions of SAO Below!
Wrote them in a way to excite you to know more when you watch them.
He doesn't stop at threats in Abridged.
The other difference is the game itself. In the abridged version acts more like a game from our real world than something Isekai like the setting of Sword Art Online. It's also full of bugs which makes the death game more lethal! Abridged explores how the bugs it introduced affects the players of SAO as whole, which is a sign of good writing.
In the original, many characters have played as girls that Kayaba have changed back into guys. In abridged, all of those had a girly name for their avatar, just look at "Tiffany."
If the original is a pure power-fantasy story, Abridged is a deconstructive-parody of power fantasy, (one example of this type of parody is KonoSuba,) the type of humor it chooses however is a dark one.
Kirito's in the Original
Kirito in the original Novels/Anime seems to be the "perfect guy" at first but is in fact a flawed character. In writing, a flawed character is better than a perfect one, no one likes perfect guys. The problem in the original is that Kirito's flaws aren't explored in the story. Some of the flaws are contradictory to what we see in the story, (like his claim that he can't make friends, yet almost every girl he encounters wants to be his.) Novel Kirito is better than the anime one because you can see hesitation in his thought pattern, but anime only shows his actions which are too heroic and overpowered for Kirito to feel human to us.
Crying Kirito is the cutest Kirito!
Another thing with Kirito is that he was written as a blank character that the reader/watcher can self-insert themselves into. (This trait is abused to the ground by SAO franchise's games.) If you thought of him like that, Kirito suddenly feels he has a lot of personality, because a self-insert barely needs any anyway. As a power-fantasy main character, Kirito plays his role right, and slowly develops into his own character.
If you hated power-fantasy self-insert characters, you might think this is a bad writing, but it's just another genre of writing that works on different rules and has its own fans.
Kirito's character develop in the two years he spent in Aincard, but the problem is that %95 of his character development happens off-screen. For example we see the trigger for his loneliness in Ep.2 but he joined a guild in Ep.3 only for it to go horribly wrong and becomes even more lonely. Ep.4 drops this altogether and by the second half of the arc, Kirito's personality totally changed. The reasons for change are only implied and not shown. (Asuna defrosted his heart as he did hers.) You don't expect all the audience to understand such a drastic change. (Those who are like me however, appreciate such change in Kirito's personality.)
Many people who hated Kirito's personality in the first two seasons loved his personality in Alicization. He feels like a different character but in a way that is easy to understand. One of the reasons I think is that we see his character development in that arc. He's not as overpowered. And his hesitation shows. Instead of being a nice, confident and overly powerful guy who has no reason to act as such like we saw him in the arcs before.
Abridged Kirito's Journey to Humanity
Abridged Kirito is the biggest jerk in the series. He's almost a heartless monster at the start of SAO Abridged. For many however, he's still more likable than the original Kirito. One of the reasons is that his character changes after every encounter, in a way that is easy to understand.
So Kirito starts as this jerk of a guy who helped Balls (Abridged Klien's joke character) to train just to show off his power as a gamer. After everyone got stuck in the game, (Oh My God! If we die in the game, we die for real!) Balls asks him to help, but Kirito runs aways because Balls calls him on his jerk behaviour.
By the second episode, Kirito is so bad no one wants him in their party in the first boss's raid. He joins with Asuna as she doesn't know how to open the menu and probably no other group let her her join them. He did beat the boss with her help, and shows off how big of a jerk he is not only by mocking everyone in the room for being weaker than him. He also made a deal with Asuna, knowing fully that she can't open the menu for him to give her the item she wanted.
In episode 3 he was blackmailed into joining a guild, the only girl is the groupd Sachi, has a laggy internet connection (which is lethal in a game like this.) Other than her and the leader, the rest of guild members are NPCs who are taken from quests that the leader never finished. Sachi runs away one day because she's afraid of her lag. Kirito finds her and they have a heart-to-heart about his jerk attitude. He promises Sachi that he will become a nice person. She dies! Broken Kirito embraces his dark side for the next few episodes.
Episode 4 shows us how insane Kirito has become. He got rid of his feelings. He trained so hard, he became so powerful he started of thinking of himself as a god. He saves a girl for no reason, but something she says triggers his PTSD (that he got because of Sachi's death) and he helped her despite his complains. You can't help but sympathise with Kirito as you hear him cry Sachi's name at night. Rosalia from the same episode is a villain who studied psychology, she attempts to break Kirito only for him to kill her cold blood. (Something the original Kirito will never do.) In the end, Kirito who didn't feel anything by killing Rozalia, realizes the value of feelings and decided to have them back, so he can enjoy revenge when he needs to.
The series become better when you realize that Asuna is the same level of broken as Kirito. She's the only one unfazed by his jerk behaviour. She's as heartless as him when a fight starts, but at least she pretends to be nice to people. (Also, she's racist in the most funny way possible.) It becomes even better when you see their daughter Yui being as messed up as them! The whole family is broken!
Every episode has Kirito change in some way. Little by little you see Kirito gaining faith in humanity. By the end of Aincard, you could look back and see how far he has grown. Abridged Kirito now is one of the deepest and lovable abridged characters ever, while still being a jerk.
Of course, Abridged Kirito as a character has its own set of problems and not everyone will like him over the original Kirito, but it shows that the writers of the abridged are as invested in this. I think SWE team knew exactly how to balance a character and how to make us not hate this jerk. (It helps that the audience of SAO Abridged know that this is a parody and to not be taken seriously.)
Despite all of what I've said, I like both the original Kirito and the Abridged one. By the end of Alicization, I prefer the original over the fan version but you never know where the abridged Kirito will go from here. (We only get 1 Abridged episode per year after all.) I think enjoying both is better than arguing about who is better.
One thing I can say for sure. The writers in Something Witty Entertainment are very good. They turned into what amounts as a fanfic into one internet phenomena and I hope I can do something as big one day!