THE PROS:
There are many, many pros to this new edit. Here are the most major ones.
1) Re-Focusing the Story: By far the greatest strength this cut of the film does is it brings the focus of the story away from unnecessary distractions and back to Bilbo. As a trilogy, Bilbo seemed to get lost in the shuffle, especially in the second two films. In this cut of the movie the titular Hobbit remains front and center. This change makes the film truer to the novel while also making the character development and through line far more evident. From the line where Bilbo claims he’s “never stolen a thing in his life,” to the end where he has committed numerous burglaries, all of which pivotal to the plot, the film is now about Bilbo's growth, as it should be.
2) Losing the Fat: The entire trilogy is around 580 minutes long, but this edit cuts it down to a mere 240 minutes. If that still sounds long to you, then remember that Gone with the Wind is nearly that long, and the extended edition of Return of the King is even longer. This makes it a long single film, but still a single film you can feel relatively comfortable watching in one sitting.
3) Getting Rid of Distracting Side Quests: Obviously I am talking about Gandalf and Radagast’s Dol Guldur storyline, but this also stretches to the side story of the fall of Durin’s Folk and Thorin’s missing father, as well as Azog’s quest for revenge. Some parts of these side stories are better than others, but overall they are all rough and uneven regarding quality. Worst of all they distract from the main story. Losing them means that you may not get an extended backstory on each character, but it's worth it.
4) Legolas Becomes a Cameo: Legolas has some of the most ridiculous action scenes in the Hobbit films, and that's saying a lot. Whether that be running on falling stones, riding a troll, or tap dancing on dwarves heads as they barreled down a river. Nothing he did in the films contributed to anything, and all the while we knew he'll survived. All his scenes were just filler, and you lose nothing by cutting the majority of them. Instead, Legolas is now relegated back to a comfortable role of a cameo and works as a more simplistic nod back to Lord of the Rings or, for those watching the series in order, a tease of the character to come.
5) Getting Rid of/Reducing Irritating or Added Characters: A bunch of other characters appeared that weren’t in the books. The must notable being Taurel, Radagast, and Alfrid. The two are abominations in which every scene they were in is cringe inducing. Radagast is cut entirely thankfully, while Alfrid is now barely in the movie and only has a few scenes. Taurel is reduced so much that she is now practically an extra and just another elf face in the crowd.
6) No Forced Romance: It’s understandable why Peter Jackson included an elf lady to the film. The movie was overflowing with testosterone, and there are absolutely no female characters other than the ones added. But Taurel ended up being a waste of a character who did nothing in the story overall. The greatest sin though was spending so much time on a love story that didn’t work, wasn’t believable, and did near nothing. Cutting it also greatly helped the pacing. Speaking of which….
7) Improved Pacing: All the Hobbit films suffer in some part of having the films grind to a painful halt. The most obvious example being the Rivendell scenes in the Unexpected Journey, where the movie gets stuck in a boring, slow, rut. Many of the painfully slow scenes are trimmed or removed, improving pacing in the long run. The opening is also mercifully condensed from 45 minutes down to 30, without anything feeling missed.
8) Color Correction to Lord of the Rings: Now the Hobbit should be a different tone, but a lot of the light color correction from the official movies were a little over the top and many times called more attention to the CGI in the film. The color correction is brilliantly adapted for this edit to be closer to that of the original Lord of the Rings Trilogy, offering greater continuity in the visual tones.
9) The Backstory to Dwarves Feels More Organic: Instead of seeing the back story to the Dwarves through a lengthy narration we instead learn about them with young Bilbo at their house during their conversations and in their eerie campfire song. It’s more true to the book and works better as the world around Bilbo expands as he journeys further away from home.
10) No Over the Top, Forced Comedy: Fear not. A lot of the charm and comedy remains intact in the film. What we lose is the over the top, forced comedy such as abundant fat jokes, fart jokes, and CGI nonsense jokes.
11) Azog's Role Reduced: He still plays a pivotal role, but his scenes have been reduced and he is now more of an off-screen threat, mentioned many times in passing but rarely seen. His role is now more comparable to that of Lurtz, an original Orc created for Fellowship of the Ring.
12) Improved Musical Score: How is this possible, you might ask? Well, some of the musical cues from the Hobbit were a little too blatant of call backs to Lord of the Rings. Some of these areas have been improved. But the most dramatic addition was the editor added the fantastic Misty Mountain theme from Unexpected Journey back into appropriate areas of the film, turning it into the equivalent of the main theme of the Lord of the Rings.
13) Battle of Five Armies is Better Paced and More Coherent: The final film in the Hobbit series was a mess and overblown. This edit cuts in most of the good stuff, leaves out the bad and improves the overall coherence as well as making it flow better with what is going on with Thorin and Bilbo.
14) Getting Rid of CGI Cartoon Sequences: This edit is second only to Bilbo being remade as the main character as the best edit. It does away with nearly all the over the top cartoon sequences. Only a handful remain and are only there because of story reasons. Gone is the over the top Goblin Cave shots, Radagast’s ludicrous sled chase, the clusterf*ck barrel ride, head scratching lava surfing, stupid liquid gold statues, and bombastic Legolas action sequence. This grounds the movie back into some semblance of reality again and adds more believability as the heroes are no longer defying gravity.