He is placed 5th on the official tier list in the A tier, an improvement over his already strong 10th out of 38th placement in Brawl. This very high position is largely due to his high weight and great mobility, edgeguarding, and combo game.
Wario is a very heavy, but very mobile character. From Brawl, he maintains his incredible aerial mobility and the notorious kill move Wario Waft. These two attributes often lead to him being described as a "Fat Jigglypuff," though the two are quite different. Wario lacks a strong recovery, but his high weight makes it more difficult to knock him off the stage. His re-purposed Chomp combined with his aerial mobility gives him one of the best grabs in the game. His lack of a projectile or significant disjoint makes it somewhat difficult for him to deal with characters that have those traits.
Changes from Brawl to PM
Wario has received both buffs and nerfs in the transition from Brawl to Project M; however, he has been significantly buffed overall. He has received a plethora of notable changes in his moveset to further aid him in the new metagame. It is also now much more reminiscent of his appearances in the various Wario Land games. Many of his moves have decreased ending lag and many of his moves have either been changed completely or have seen heavy adjustments giving them a lot more utility with some examples including his down smash and his down aerial. Wario Waft also charges much faster and is a much stronger KO move when fully charged. His new side special Shoulder Bash is also a much better KO move than his previous side special Wario Bike. He also benefits to the changes to Project M's grab release mechanics more than any other character as he is no longer vulnerable to air release combos, kill confirms and chain grabs.
Wario has received some nerfs however. His previously incredible aerial mobility has been slightly toned down and his recovery is much worse as his new side special Shoulder Bash covers far less horizontal distance than Wario Bike while covering no vertical distance and leaving him helpless and it has less utility on stage in addition. Wario Waft also covers much less vertical distance when fully charged in addition to dealing much less damage and the half charged variant is much weaker. Besides his half waft, some of Wario's other KO moves have also seen significant nerfs as his forward smash is weaker, has more ending lag and no longer has armor while his up aerial deals less damage and now has a sourspot making it more difficult to KO with. Lastly, his down throw is no longer a reliable deadly chain grab due to having much more base knockback as well as due the general changes to PM's DI system.
Nevertheless, Wario is an even larger threat in Project M's meta and has seen even stronger tournament results.
Grabs and Throws
As of v3.6 Beta, Wario-Man can now be selected as a character, in a similar fashion to Giga Bowser. Much like how Giga Bowser lost his constant armor, Wario-Man is no longer invincible for the duration of his appearance, and his recovery is no longer infinite, though Wario-Man can still gain significant distance using his extra midair jump and height gain from neutral aerial and up aerial. As expected, Wario-Man is still an exceptionally strong character, with the following noticeable changes from Wario:
Changes from PM to P+
Up to date as of version 3.6.
In competitive play
Wario is the only character that did not receive a single new costume in Project M. Worth noting, however, his costumes changed order when compared to Brawl, where his WarioWare costume is the "main" one. Instead, in Project M his Wario Land costume is featured more prominently, most likely to better represent the changes to his moveset that mainly take inspiration from that series in particular.
In Project+, Wario has a new costume based on his appearance from WarioWare: D.I.Y., the costume also comes with five recolors for Team Battles. This makes Wario the character with the highest amount of costumes in the game, with 18 in total (or 20, counting the secret ones).
Z-Secret Costume: Adventure WarioR-Secret Costume: Wario Land Garb Wario
Z-Secret Costume: Ninja WarioR-Secret Costume: Vampire Wario