This is the current revision of the official tier list created by the Smash Back Room, ranking each character in SSB4 from best to worst based on votes from over 53 professionals at said game, current as of version 1.1.7. Please note this list doesn't account character customization, due to their collective ban post EVO 2015 in competitive play. Also, please note that Mii Fighters were excluded entirely from the tier list due to a large stagnation of data on them, and their legality being pretty shaky. Finally, Pit and Dark Pit were voted on as the same character due to them being almost entirely the same in every aspect.
Also, it is important to note that you should not let the tier list be the deciding factor in whether you main a particular character or not. Of course, a character's individual standing is an important factor-it always is-but in the end, the deciding factor on whether you choose to main a character or not should be how you personally feel playing that character and how much fun you have playing with him/her. Now, on with the rankings!'
These three characters are the ones that, far and wide, are widely considered to be a cut above the rest. Their weaknesses are there, but their strengths are abundant and more than make up for their shortcomings. You must be able to do well against at least one of these three characters, or else you're toast.
1: Bayonetta: If you were a competitive player back when Bayonetta was made available as DLC, you'll concede that it's no exaggeration to say that there was just no ignoring her. Due to being very easy to pickup and yet offering an insane amount of strengths with little weaknesses to counteract them, Bayo players quickly flooded the scene and began utterly crushing at the national level in no time flat, stirring up immense hate and controversy in the competitive scene, due to her 0-Deaths simply being way too good, and it didn't help that most of the people playing her did little outside the same old "Heel Slide to double After Burner Kick to Witch Twist" 0-Deaths over and over again). Even after getting slight nerfs in 1.1.5, she was frequently compared to Brawl Meta Knight in terms of how sickeningly overpowering she was, and she had actually been banned in a few regions.
Fortunately, that was then. After 1.1.6 nerfs brought her down to Earth, she can still 0-Death you, but she isn't so easy to play now, and now her weaknesses are pretty exploitable and now, only the most intelligent Bayonetta players will thrive with her. Her untapped combo prowess and her fierce ability to make opponents pay for their mistakes still establishes her quite well as the best fighter in the game, but she's now pretty manageable for most of the cast, and has become a very over-hated character.
2: Cloud: Much like Bayonetta right above him, Cloud has become a pretty powerful character, but not to quite the same extent. He is a solid character that blends range, power, and speed, making him a consistently reliable and strong fighter, not even getting into his big draw; his Limit Break adds a whole layer of cheap versatility to his moveset; all of his Limit Break specials blend ease of use with ridiculous KOing power, all in all making Cloud a devastating character that, while relatively back and forth early on, soon made his presence known. Not to say he is completely flawless; his biggest weakness remains his abysmal recovery, which is about on par with Little Mac's without Limit Break boosts, which many top players (such as one of his best players, MKLeo) claim is too bad for safe high-level play. In spite of his enormous strengths and being a fundamentally powerful pick for casuals and experts alike, you can make the argument that his placing is rather violate.
3: Diddy Kong: A very far cry from his widely detested pre-1.0.6 self, Diddy Kong's future was initially in doubt after he lost his widely hated Hoo-Hah death combos, and while no longer utterly loathed by casuals and professionals alike, he still remains an effective choice; this was shown by his players adopting a much more creative and varied playstyle to get around these nerfs, emphasizing his other strengths, like his great ability to adapt to the flow of a match and switch it up accordingly to keep Diddy Kong a strong pick. While certainly not the most consistent when it comes to results (on good days, he can outpace even Bayo and Cloud, while on others, he can find himself outclassed by lower-tiered characters), all in all, he's a solid, strong option who is generally agreed to be just right where he is now.
4: Sheik: Sheik has certainly changed quite a bit since the early days of Smash 4. While her almost unrivaled combo power, attack speed, and ability to seamlessly weave between offense and defense have always made her a very strong character in the metagame, it wasn’t until the noticeable nerfs to Diddy Kong and Rosalina that she would truly begin to shine; without those two characters standing in her way, it paved the path for her to rise to the top of the chain; her strengths were showed off by a very talented playerbase (consisting of players like the infamous ZeRo, who would go on a large 56-tournament win streak with a skilled combination of Sheik and Diddy Kong), and led to her near-unanimously being considered the best character in the game. Eventually, however, she received some pretty significant nerfs in 1.1.4 and 1.1.5 that exacerbated her shortcomings (such as lack of KOing power) and toned down her overwhelming strengths; this had an immediate effect, with most of her best players (including ZeRo) finally dropping her/using other characters more often. However, much like Diddy Kong, some loyal mains continued to show she is still a very viable character with lots of potential. While her lack of major tournament wins compared to the top 3 have finally caused her to sink down below the highest tier, she has maintained a very positive light and her future holds many possibilities.
5: Rosalina and Luma: With her unique 2 in one mechanic having infamously granted Rosalina near limitless combo possibilities, it's no surprise that she has also been a top tier since the beginning. Even in spite of her learning curve preventing her from gaining a significant playerbase, thus making her a comparatively rare sight in tournaments, and she herself having some issues against other top tiers, she has overall the most dominant matchup spread in the game, owing to all the low tiers she just absolutely wrecks, and she continues to leave a strong impression.
6: Zero Suit Samus: Not only is she one of the flashiest characters in the game, but Zero Suit Samus has also proven to be amongst the top dogs. Not only is she one of the fastest characters in the game, and not only is she an all-star in the air with all of her aerials packing insane versatility, but her sheer ability to punish the foe’s mistakes and capitalize hard (like, REALLY hard) with moves like Paralyzer, down smash, and hyper-powerful combo enders like Boost Kick and Flip Jump, it shouldn’t be surprising that she has continued to go very strong and has gained constant tournament success throughout the game’s entire lifespan. While players have learned to exploit her weaknesses (such as her poor neutral game and being both easy to combo and easy to kill), she remains a well-established character with great peaks and great potential.
7-8: Fox/Sonic: As a pioneer of the "hit and run" archetype in Smash, Fox Mcloud has been a perpetual high/top tier ever since Smash 64, and he's still hanging in there. The reason behind his consistent success is simply how well his toolset works. With the basic tools he has, he is practically destined to never be worse than mid tier. He maintains his signature blazing fast speed, his zippy frame data, solid combo games, and his solid gimping potential. On top of all that, he benefits heavily from the changes made to the mechanics in Smash 4, most particularly the removal of chain-grabbing and the changes to hitsun, which plagued him in Brawl. In spite of significant shortcomings like his horrible endurance, he has continued to go strong with near constant tournament success, like Zero Suit Samus right above him.
The Smasher sharing 7th place with him, Sonic, on the other hand.... has certainly seen better days. Make no mistake, his heavy buffs from Brawl certainly helped to migate his flaws, in fact, many would argue they helped too much. In addition to his signature speed, his awful KOing power was addressed, and his Spin Dash specials were buffed to the point where they were (and arguably still are) amongst the best neutral options in the entire game, and his spammy and defensive playstyle only helped to make him a more unpopular character amongst the Smash crowd (matches with him often went to time because the Sonic player kept stalling. Naturally, he was quickly nerfed, and while not quite as annoying to fight against, his popularity and results are currently overshadowed by everyone above him, as his best players either don't travel to the US anymore or are semi-inactive. His future could go anywhere.
9: Mario: Mario is one of the best characters in the game. His versatility and fluent combos make him one of the best characters, but his one big flaw is his +. It is one of the worst +'s in the game. It has a high chance of being gimped by someone like Zero Suit Samus.
16: Meta Knight:
19: Captain Falcon:
20: Princess Peach:
22: Donkey Kong:
23: Toon Link:
27: Mega Man:
30: Duck Hunt Dog:
32-33: Pit/Dark Pit:
39: Mr. Game and Watch:
44: Little Mac:
48: Bowser Jr.:
49: Dr. Mario:
51: Wii Fit Trainer:
52: King Dedede: