Well, seeing that these personal MU charts are becoming the norm (and I'm sure all these images are fun to look at), I'll spout mine, on my main ROB. Info comes from ROB boards wip MU chart, tournament speculation, and personal experience at locals & online.
against the supposed top tier:
Opponent's favor (in order from least manageable to somewhat manageable):
Even-ish:
Slight advantage:
To put it bluntly, I am surprised ROB is rated so highly on the "top 15". Yes- he has tourney results, is one of the better item users, has a good throw game, and has good aerial disjoints- but he suffers against pressure. Pikachu, Villager, Mario, Rosalina, and Sheik have stellar defensive walling games, and completely outclass ROB in one of his best attributes. Simply put, they can force approaches. Fox, Zero Suit, Meta Knight, Yoshi, Captain Falcon, and Luigi all have great combo potential and when they do get in, it's very rough for ROB. Zero Suit, Luigi, and Falcon despite being mobile monsters and combo fanatics are kind of messed up by gyros. They also can't recover quite as well, as the other top tiers (which is good for ROB with one of the most useful spikes in the game). Still, they can mess up ROB in the air and are rewarded plentifully off throws.
Sonic and Diddy were nerfed more than ROB. An on-stage gyro and lasers probably work the best on these two (Sonic's spin dash technique is halted and Diddy cannot hold 2 items in his hand). As for the Pits, I am surprised they are rated this high, as well. Nairo is good with them, yes, but these two have odd multihit frame data and very exploitable laggy specials. Like ROB, they aren't terrible, but they don't follow the same offensive based play that the other top tiers do. ROB can camp Wario and Lucario, which is nice. ROB doesn't have a problem with the bike and Lucario can be killed in a last ditch effort up throw (if he doesn't die to a Dsmash/up air/reflected projectile at 100). Don't know enough about ROB vs. Brawler/ Olimar, but they are both pretty well rounded characters that aren't to be underestimated.
ROB is pretty average, in his kill power, combos, and defensive game. Unfortunately when the top tier is just so rushdown/ safety/ camp oriented, ROB can't do much. He's viable, but I can imediately think of 8 characters who can compete better with the top:
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