
Hmm...
I play Smash online probably an average of 5-6 hours a day. (I usually play in the early morning.) This list is meerly based on my experience and not on matches that I've played with people outside of "anyone." I have seen good players with just about every character and others that would make you laugh and cry at the same time if you watched them play simply because of how terrible they are. As someone else said, no one has truly mastered anyone yet because people are still discovering things about all the characters. There are characters, however, that "nOObs" (sorry, I hate internet slang...) use because of certain traits that make them easy to win matches with "anyone" with thus creating the illusion that they are good with certain characters. Still, these are my observations:
Top 5 Easy to Use/ "nOOb" friendly characters:
1. Ike (Playing more then an hour of online matches makes this more than apparent. During that time period, you are more then likely going to run into at least one person who does nothing but spam attacks. Here's how they usually play: Always start the match with his B smash attack, spam his fsmash when people are in front of them, spam his dsmash when people are behind him, spam his usmash when people are above him, use his fair while jumping only to miss 95% of the time, spam counter , his A combo, or aether whenever he gets stuck in a crowd, and use Eruption whenever he's coming down after being blasted upwards. These people rarely dodge, shield, or think.

They are usually very easy to predict but, sadly, people still fall into them when they don't pay attention and get KO'd. I'm sure everyone has lost at least one match from someone like this.)
2. Pikachu (Another spam friendly character. Dsmash, thunder, thunder jolt, Fsmash, Skull Bash, repeat... There are few things in Smash more annoying then getting caught in a Dsmash and most people don't know that you can actually DI out of the top of it so you'll only take about half the damage and leave you in position to counter if your percentage isn't too high. Besides Ike's forward tilt, Thunder is probably one of the biggest KO stealers in the game because you can kill people that are falling from as high up as the top of the screen with it.)
3. Kirby (Are you beginning to see a pattern?

These are the people that fly to the top of the screen, use Stone, and even if they miss, use his hammer swing upon transforming out of it and then fly away to do the whole thing over again. Common habits they often use are abusing Kirbycide, final cutter, and his fmash. Again, really annoying players if you don't know what you're doing which is probably about half the people who play online. Yes, contrary to popular belief, there are some pretty good players who play against "anyone" but you usually have to wait until after 10 PM to play against them(which is basically the reason why I play so late).)
4. Pit (Do I really need to say anymore?

Spam his smash attacks, his arrows, and his B forward. YAYAYAYAYAYAYAYAYAYAYA!

)
5. Metaknight (What attack of his can't be spammed?

Metaknight is one of my mains and it saddens me that so many people blindly attack with him instead of thinking things through.)
Top 5 Hard to Use/ "Master"
1. Jigglypuff (People usually don't even try with her. Most of the time, they'll just fly off to some corner and taunt or sing repetitively and fly away if someone approaches them or just wait for smash balls, hammers, pokeballs, etc. Even if you know what you're doing, it is still hard to win matches with her in "anyone' matches. If you do win a match with her though, expect your competition to drop out of the next match.

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2. ROB (This character has a ton of little tricks that people don't know how to use properly or don't even know about.)
3. Wario (See above)
4. Snake (He's so unorthodox but, for some reason, a lot more people have taken the time to learn his various tricks unlike the other characters on this list.)
5. Bowser (There are only two kinds of Bowser players: those that are scary good and others that are herrendously terrible. 95% of the people who play as him are in the latter category.

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