Honestly, Mario isn't very good at all; he's definitely worse than both Ness and Lucas. Look at it from the perspective of a Mr. Game & Watch player; I'm not scared of any of the three of you because he definitely has an advantage on all three. However, you all have different things that can be problems for me.
Ness is the most threatening of the group. His forward aerial is very good at protecting him in the air, and all five of his aerials in general are reasonably good at challenging my air game by matching my range and damage with knockback power and speed. All of his smashes have a lot of range which means I can't just play ground spacing games against him all day either. He kills me super low from a grab, and he has a great dash grab. PK Thunder 2 is terrifying in the sense that, while I really can usually avoid it, it's a lot less easy to punish than it seems, and if I do happen to get hit, I'm in trouble.
Lucas is the middle guy in terms of being a threat. His aerials aren't nearly as good as Ness's, but his down aerial is still way too good and really is going to hurt me badly if I get caught in it. Lucas's forward smash is a top tier threat that can easily challenge all of my smashes and has no trouble killing. Lucas's recovery is amazingly good when you factor in zap jumping and that crazy thing he does with PSI Magnet to fly halfway across the stage; he's pretty much ungimpable. Tether grabs are also deceptively good against Mr. Game & Watch, and Lucas has, if I recall, the single best grab pummel out of the cast. He also has high quality moves like neutral aerial, jab, and down tilt that rack damage well; I am not worried about my ability to beat Lucas, but he keeps me on my toes!
Mario has... what again? His aerials all have laughably bad range so I can just throw my stuff at him all day in the air, and he can't do anything about it. The fact that he has no ability at all to defend himself from the front since his forward aerial is the single worst aerial in the game makes it way too easy to mess with him when he's recovering. Mario's Fireballs are worse than Pk Fire which wasn't significant enough to even list for either Ness or Lucas. The Cape is a joke; I have lots of moves that are effective regardless of which way I'm facing, and you are not gimping my recovery either way. F.L.U.D.D. is garbage; I don't care what you guys have convinced yourselves of otherwise. Any gimping tool that can be avoided by EITHER recovering too high or too low is obviously garbage. I'm not sure where the idea that Mario is good at combos came from, and it wouldn't matter anyway since Lucas does more with his down aerial than Mario does with 3-4 of his random weak hits. Mario's only two things that actually make me worry are his partially invincible up special and his forward smash. His forward smash is actually a really good move all around with solid range, power, and speed, but it's not as good as Lucas's forward smash regardless. His up special just doesn't do nearly enough when it hits to make up for how badly Mario is going to get owned when he misses; it's a good move, but it's not nearly enough to make Mario as a character.
I notice a lot of people like to say that Mario is "well rounded" so the fact that he has almost no strengths is offset. Even if that were true he would still be a bad character (jack of all trades is the worst role in any game unless you're above average at everything), but he actually has a lot of really bad attributes. His range is really no better than what Jigglypuff or Luigi have; that's the class of "worst range in the game except Wario". Did I mention that range is overall probably the most important character attribute in brawl, and if you have bad range and don't have especially good mobility, you have pretty much no way to actually hit half of the top tier? His recovery is pretty bad; it's probably in the bottom 10 out of the cast, and he gets to join Link as one of those rare characters who actually has to worry about not being able to get enough distance to make it back. He is also one of the worst characters at avoiding gimps because his forward aerial doesn't protect him at all in the air, and his other aerials, while they are useful to him on the stage, are really just not built to help him answer someone jumping out and smacking him which leaves him praying he can use the Cape to save himself (good luck; you're going to need it). It's actually strange that anyone would bring up Ness's recovery here because his double jump + forward aerial is better for recovery overall than everything Mario has put together.
Mario isn't quite the worst in the game, but he seems obviously pretty awful. I ordinarily wouldn't go into a character board to explain why your main is bad, but when people who use Mario, of all characters, start to call other characters garbage, they obviously have some bad perceptions. Yeah, your character is better than Ganon, but to be brutally honest, that's not even that comfortable of a lead... You're free to have fun with your definitively low tier main, but you need to be honest with yourselves about just how good your character actually is.
