Neutral: Neither of these characters really have any advantage in neutral since they really lack any kind of projectile or way to force each other to approach = +/- 0
Roy at an Advantage: Roy is at an advantage when he is rushing down/pressuring Marth since Marth is at his weakest at close range, has very few options when being rushed down, as well as Roy having the most damage output while rushing down due to Tipper hitbox placement = +1
Roy at a Disadvantage: The disadvantage comes from being completely shut out by Marth's superior disjoint range and proper spacing. The only real why to prevent damage is to shield but that also leaves Roy open to Marth's long grab range. The only advantage Roy is at a disadvantage is that because Marth's has a somewhat limited combo game, Roy doesn't have to worry about being combo as much and has the ability to DI out of most of Marth's combos which can potentially leave him open = -2
Roy Edge\Ledge Guarding: Most of Marth's recovery options come from two things: Dancing Blade and Dolphin Slash. Dancing Blade stops Marth's falling momentum and moves him forward a little, while Dolphin Slash sends Marth up quite a bit at very high speed. Unless Marth is recovering above the stage, Roy very few safe edge-guard options aside from Flame Sword, which is limited by the fact the move mostly hits in front of and above Roy = -1
Roy on Recovery: By far, Roy's worst aspect in this match-up in that because of high fall speed and relatively short recovery, he is easily gimpable. it also doesn't help that because of Marth's range he can easily and safely gimp Roy simply by using Fair offstage = -3
Roy Far away from opponent: Same situation as neutral. Since Marth really doesn't have long range options, he can't do anything to Roy at long range = +/- 0
Roy at mid range away from opponent: The place Roy never wants to be and where Marth shines. at mid range is where most of Marth's tippers connect (I.E: Fsmash, FTilt, Dtilit) and allow him to get most of his big damage and even early kills. Roy's attacks at this range either don't land the tipper or don't connect at all. However, Marth can't use his range to apply pressure, which prevents the match up from being completely one-sided = -2
Roy in close range: In a similar but opposite fashion, Roy excels in close combat and against Marth this is extremely apparent. All of Roy's tippers connect and help him deal big damage very quickly.He can apply a lot of pressure, do powerful mixups, and his combo game is dominant while close to the opponent. Marth is weak in this position since he can't land tippers and he can do is up b to safely get pressure off him = +2
Tl;dr: I'd say it's 45-55 match-up in Marth's favor; Roy will utterly dominate once he gets breaks through Marth's range, but the problem is getting through with getting too much damage or killed.
