Also, to keep the Ness vs Sonic foolproof, I pretty much gone up against a good Sonic player in a six minute match and I ended up getting six points in that six minutes while Sonic on the other hand never got any points. He only got me up to 207%. This happened because the barrage of PKF, the yo-yo, fairs, nairs, bairs and dairs. But than again it could just be because Sonic is very easy to read. Either way, Sonic's speed is his disadvantage and he really has no mindgames.
Your definition of good is skewed. What, did he have no control over his own dash? Did he run into your PKF without shielding? Did he run/spindash straight into yoyo? Fail to airdodge through a projected D-air spike after an up-B? Did he not use feints, cancel moves at all?
Hardly sounds "good" at all, unless you're comparing him relative to other people locally.
A friend of mine said he was the best among his friends with his Lucario and Ganondorf and wanted to try me when I used a certain character. I had had more experience with other people who had mained those characters, and on player patterns in general, so I 4stocked his Ganondorf (out of 5 stocks) and 3-stocked (out of 5) his Lucario. Did that mean that my character had an advantage over them? Heck no, especially not against Lucario. I just outplayed him and overwhelmed him with a character and style that he had never seen before.
Ness has the advnatage over Sonic. Dtilt+yo-yo=No spin
Ness also is NOT at a disadvanatage to Squirtle. Range.
I gave up on that chart. Its totally wrong and I dont think it's gonna be fixed the right way. The happy happyh cult at All is Brawl has a matchups discussion.
Of course, it's not like Sonic has aerial spin attacks or anything. No, he only uses ground spins.
From what I've experienced playing against Sonic players, the best way to counter him is to simply jump. It pretty much forces him in the air and, because his aerial mobility is garbage, can easily be countered by most characters. This is one of the reasons why the Sonic vs Wario matchup is complete ****. I've also learned that you can grab him out of his rolls too but the timing is kind of difficult.
It's not so much his aerial
mobility that makes the Sonic vs Wario matchup so bad for Sonic, it's more of Wario's higher priority and (well timed/placed) bite.
==========
However, this is not to say that Ness doesn't really have an advantage over Sonic-
F-air and N-air give Sonic trouble because they are pretty high priority aerials, and PKT's ability to create disruptive walls of damage with the tail can make it a pain to try to attack Ness, depending on position. However, offstage, Sonic's spring [projectile] can be used to slow down PKT2 if dropped in front of it, or to stop the PKT1 altogether by blocking it. If Sonic is under Ness, he just has to aim himself and spring straight into the PKT1 before it reaches Ness.
PKF is escapable with some upward DI and spring, if not, spring by itself. It generally doesn't bother me unless I'm playing online and fail to pshield it.
Yoyo moves have certain openings (D-smash can be attacked through the air, and U-smash can be attacked/grabbed during the "round the world" motion) that can be taken advantage of, but they
can stop grounded spindash, as previously stated. To a lesser extent, Ness's dash attack can be troublesome for Sonic, because of its disjointed hitbox, but it's less of a problem than F-air since it can be shieldgrabbed.
However, Simna pointed out in a discussion with me over this matchup, with correct DI, Ness shouldn't have to be in the situation that he's under the stage or 'ground level' off-stage.