I like bubbaking's tier list because I really think it reflects the metagame right now, but I'd put Falco above Fox because he has a much better projectile. I'd also move Yoshi up above Young Link, but as stated previously, his results don't reflect that at the moment.
I also think Ness has a little more potential, and I'm not saying this just because he's my secondary. If you look at players like Mofo and Hungrybox, you can see that Ness can combo fairly reliably, and his F-air poke is insane. Also if you check out the 2nd match of Mofo vs Hax you'll see how awesome the Yoyo Glitch is in competitive play. All of Ness' aerials are good, but he suffers from having an easily gimpable recovery and terrible up and down smashes. F-tilt is surprisingly strong and can catch someone off guard if they're trying to recover. U-tilt and D-tilt have their uses as well, and his back throw is probably the strongest throw in the game. The main problem I find with Ness is that you can't be aggressive or you'll usually get hit when doing a DJC aerial, which forces you to play rather defensively.
With that said, I think Ness should be right under Mewtwo on bubba's list because he doesn't have any super extreme weaknesses that the characters in G tier do.