Two characters I like a lot from two verses I can actually say I know a lot about! Even if my knowledge is a bit outdated.
But that isn't here or there, here are my impressions!
AP: Brad is likely the stronger one here by how much he grows over the course of the game + his stat-amping tools and move that cause higher damage than normal. Guts, however, can concentrate a higher amount of force by the edge of his sword, and isn't so far behind that he should be easily overwhelmed by Brad overall. So, Brad has an advantage in the raw exchange of blows, Guts can hit "harder" on a clean strike with his sword.
LS: Brad is stronger, both in feats and by the profile. I protest Guts' current LS rating, but in any case he should be weaker than Brad at this key, particularly during the Griffith retrieval arc. Guts fights dirtily enough and with weapons to counter Brad's grappling up to a point, but he should hold the LS advantage quite solidly.
Toughness: Both are very similar really on how they can persist fighting even with grievous injuries. I'd even say that Black Swordsman Guts would have the advantage - but here's the thing, during the Griffith retrieval arc, he didn't have the kind of insane bloodlusted willpower he shows later on. So, I'll give the advantage to Brad, but both should have more than enough tolerance to pain, wounds and tiredness to make this point moot.
Skill: Brad is absolutely the better unarmed fighter and he is more than skilled enough to confront Guts on a direct battle, but Guts has shown to be a far more resourceful fighter, having greater tactical acumen and a greater skill at using the environment and in sheer ruthlessness. I believe Guts has a significant edge on this, although Brad is very much a live dog, particularly if Guts is forced to engage on a conventional battle with Brad.
P&A: Brad has a degree of healing with his items, has a lot more range with his fire and explosions and has his nasty stat amp. Guts, for the useful skills here, has his superior mobility with his agility, and his air pressure redirecting can prove to be very useful to partially disperse Brad's fire attacks.
With that in mind and what I believe how the fighters would go at it, I favour Brad more often than not, although it would be hard and Guts can certainly pull out a win under the correct conditions. Brad has more range and tools for a direct fight, although Guts would be a very difficult and cunning opponent. Ironically, at medium-range, Guts can probably pull out more wins than losses, but at either long or close range, he should lose. And had this been Black Swordsman Guts, he would win.
Brad wins with a lot of difficulties.
