First thing that's really noticeable is Roy's attack range. While it doesn't seem to quite match Marth's, it's still really good. Also I'm not sure yet, but it seems like his grab range is pretty close to Marth's too? Would be nice to get some hitbox data for comparisons. Either way, with Roy's buffs it seems like even if you sourspot most of his aerials then can setup to combo.
So far I've had some success with:
Weak Fair -> Grab
Fair -> Ftilt (Good when they get hit too far horizontally from fair)
Fair -> Dtilt -> EVERYTHING (Only works if they're near the floor after fair)
Not sure how consistent this is but maybe a Ken combo is possible?
http://youtu.be/zcoRNbZeNtU?t=16s
If you watch closely though, it seems like the Samus recovers before the dair even starts, so it looks like bad reactions on the Samus player's part.
Judging from the
Roy reveal trailer,
3.0 trailer footage, and
Neo vs. JCaesar it seems like uair -> dsmash might work. Fair -> dsmash might work too. We need to test this.
I've tried fair -> utilt like Marth but the problem is that Roy swings his sword a bit slower and the swing starts from behind him rather than in front of him. This could work out if you quickly pivot right after the fair, but I'm not very good at it so I don't know how viable it is.
Dtilt is god-like for setups since it's great for poking feet and knocks enemies upwards. Also, because Roy still retains his god-like SHFFL speed from Melee, his uair is great for juggling when the opponent is above you, especially if they're stuck on a platform on top of you. Uair is great for setting up into more uairs, fair, and maybe even a sourspot dair. You can finish the string up with fsmash, nair, bair, sweetspot dair, and American Idol usmash which can actually do something besides be referenced under American Idol unlike Marth.
I'm not a Brawl player so I don't DACUS, but it would be nice to know if there's any situations where a DACUS would be useful. Also I'm pretty sure that usmash can be smash-DI'd out of, but there seems to be a lot of hitstun on it and it can send enemies at a weird trajectory so maybe there's an option that Roy can do to cover this issue?
I've found that dsmash seems to come out faster than fsmash so, although it's not as powerful as a sweetspotted fsmash, it seems to be a bit safer option than fsmash and has a good amount of hitstun and knockback to help you gain momentum in a match.
So far the dair is tricky to spike with for me, probably because I'm so used to Marth's. Then again, it seems like most of my flubs are due to being used to Marth especially with the fact that Roy's sword range seems to be a bit shorter, but I'm guessing that'll go away with time.
Bair is a bit hard for me land when SHFFLing. It seems to work better in an air-to-air situation, but honestly it's a lot like Ike's bair so I'm pretty sure Ike mains won't have this problem. I probably need to get used to it is all. It also turns you around like Marth's bair, not sure if Ike had that too.
Side-B seems to be pretty great for eating up shields and getting shield stabs especially when it comes to the forth downward hit. The third hit in the combo is really strong and if it lands it leads to huge knockback.
Neutral-B seems to be good for edgeguarding since you don't need to sweetspot it and it'll still have powerful knockback when it lands. It comes out relatively quickly too.
I haven't played many fastfallers yet so I can't say much about uthrow, but at low percents fthrow, bthrow, and dthrow are great setups for tech chasing.