There's not a 'best' character but there are better characters. I don't follow tiers anyway, just play who you want, that's what the game was designed for.
I only use Jigglypuff when it comes to Competitive tournaments / For glory 1v1 mode and can dominate...tbh The tier system fails if there's one already made on smashboards or some other site because you should use who you want. You'll be surprise on some of the characters people use and can dominate with
The tier system is the most accurate representation of the current metagame. It provides, basically, a list of advantages and disadvantages in every character matchup. Thus, if Jiggs becomes Robin's counter, I'll probably pick Jiggs when going against a Robin. The tier list exists simply to deepen the metagame and allow for a very rich experience.
Also, tiers ain't for queers. They exist for everybody.
Obviously some characters are always going to be overall 'better' than the others, but for a lot of people this isn't going to make much of a difference anyway and shouldn't matter. Maybe it will matter to those guys who always pick the 'strongest' ranked character in games because they lack actual skill (and continue to lose anyway).
I just use characters that I like and by that, end up becoming pretty good with the characters since I know them. Kirby has been ranked bottom in the past two games, but I've always dominated with him regardless of 'tier lists'.