my input for this will to have you guys look at the matchup summary i did for rob a little while ago.
Rob: (65/35)
General Matchup:
* Rob specializes in a very good projectile game, excellent recovery, and decent reach and combos.
* Rob doesn't have a particularly amazing amount of priority on his attacks, however he does have pretty good reach in the places that he needs it. Ftilt is probably among one of the best speed/range ratio moves in the game. This, coupled with smart use of his laser and gyro can make it difficult to approach rob. The fair, nair, dtilt, uptilt, and bair also have pretty decent range, so watch out for that.
* Rob has been somewhat notorious for lacking in the kill move department. If saved, the nair makes for a good kill move, however, due to its great versatility, rob players tend to use this move to approach and to punish in the air. The fsmash, upsmash, and bair also are decent kill moves as well, along with the upthrow (usually kills around 160 and up on gw most stages).
* Rob's recovery is interesting in this matchup. Against most characters, rob has very little trouble recovering due to how far his up b can get him. However, against mk and gw, rob finds himself in a difficult bind returning to the stage. Through a combination of up b, neutral b, fairs, dtilts, up airs, and dairs, gw can make it near impossible for rob to recover.
* Rob will probably have some of the best edgeguarding against gw that any character has. Because rob can venture so far off the stage, he has no problem dropping very low into gw's recovery path to interrupt him. Fairs and bairs can easily push gw back out into a bad spot. Keep an eye on the rob trying to interrupt you and try to get a fair/nair out before they can start pressuring you on your way back.
* Rob has some combos to take note of. Fair chaining on and off the stage is very possible and you should attempt to di away and up b as soon as possible to interrupt this. Dtilt locks against walls are also tricky to avoid in some situations given how fast the move is, and this move can be a very nice setup for grabs as well. Dthrow to upair at 0 percent can rack up a quick thirty damage, so also watch for this.
* Gw's combos are pretty run of the mill in this matchup. Rob's large frame helps gw to catch him in nairs and bairs, and also uptilt chains at low percent. Robs tech roll is a bit below average, so tech chasing him is certainly within reason given that he has a large frame to boot. Up air pressure works alright, however b sticked gyros and bairs certainly can shift his momentum enough to possibly throw you off.
General Strategies:
* When on the stage a campy rob can be difficult to deal with. Rob can very easily beat a lot of your aerial approaches by simply walking out of range and forward tilting. This will beat even the turtle approach if done right. Make sure you know how to mix up your approaches and even become over aggressive with cross up nairs or simple grabbing to throw the rob off. Also watch out for the uptilt, which will often times hit you when your above him trying to get behind him, and its even fast enough to beat your key if you start at the same time. When they move even further away, make sure to watch for the laser and bucket, the cooldown of the laser is usually high enough to ensure you won't get punished for bucketing. When facing the gyro try to avoid it and pick it up, giving you a nice glide toss approach which can get you in his face quickly.
* Edgeguarding rob is really where gw gains a large advantage in this matchup. Sit on the ledge and toss bacon if they are coming from the side or below diagonally. If they come from above dj up b will usually knock them back out. If they come from below, rar'd key near the edge will hit them. When they get closer, switch from bacon to dtilt usually, rob's will approach with aerials or try to grab the ledge. If they come from below try to get a key out like before. Dtilt beats upairs from below and fairs spaced. Jumping off and fairing can also work well in your favor if you know when to use it. If they grab the ledge, wait and shield when you see movement. If they get up attack, you can sh a fair to knock them back out. If they roll turn around and grab them/throw them out. If they get up, this can throw you off, try to predict it and grab them. If they jump from ledge, either jump nair to up b or just up b to knock them back out. If you rinse and repeat this method, they will run out of gas shortly and die. Of course smart players will have their tricks too, this doesn't mean gw will always kill rob if he's off the stage. Lasers, going under the stage, smart up b'ing can all help save the rob.
* This matchup is very simple after getting around the camping and edgeguarding issues. Make use of your range in this matchup as it is usually better than the robs in the air when they approach you. If you work your kill moves in at the right time (they have a hard time killing gw's, so you will likely not get punished as hard for whiffing) then you will likely be able to take the matchup without much trouble.
Stages:
* Rob is actually quite proficient on all the stages that gw is good on. If corneria is on certainly go for that, but other than that go for neutrals in my opinion.
* There's nothing in particular you should ban, as the stages rob is good on gw doesn't have a particular disadvantage on. Although do take note of the stages rob might be able to dtilt lock you on (you can do it back too!)