I've been hitting the lab with Roy lately, so here are my thoughts on him from a Link main's point of view:
-First hit Nair can combo into Utilt, Dtilt and jab (maybe Ftilt) pretty reliably if you time the Nair perfectly. It can also behave like Link's jab 2 in that it can set up "rock paper scissors" situations.
-Uair is a great low combo tool. Sourspot Uair can be used in the same manner only that it has fixed KB, meaning that it can be used for kill setups.
-Fair can lead directly into DB, up B or DJ Fair at low to mid %s.
-Bair is an extremely powerful gimping tool and can kill early offstage. It can be auto-canceled if you DJ back onstage from a short distance away or so.
-Roy's skid animation is super short, allowing him to use shield and attacks and such much earlier. This only adds to his already great mobility and gives him more options in the neutral. His dance trot is also very good.
-Dthrow is overrated. It works exactly the same way as Link's, only that it combos much less reliably. Still pretty damn good though.
-None of Roy's aerials auto-cancel after a SH or even a FH, which is strange considering Roy's Fair has enough IASA frames so that he can DJ after a SH Fair. It's probably that way to prevent Fair strings from being a thing, though I'm not sure why that would be such a big deal since Fair>Fair stops working at around 40%, though admittedly it would make Roy super good lol.
-Roy's Fsmash is basically a right handed, reverse version of Link's first swing of Fsmash with faster startup and more kill power (it can kill pretty much anyone at around 100%).
Overall, I love how he plays, so I'll do whatever it takes to secondary him. Roy's got pretty much everything I ever wanted from a sword character in Smash Bros.; he's aggressive, fast, has a very decent combo game and has great frame data.
Edit: I apologize if this is too much Roy stuff for you guys, I just want to share my thoughts on him.