The character I'm best at is Ieyasu. He was the first character I tried and easiest I mastered. All of his Super Arts are powerful and useful enough to use without relying on just one. Plus, his running animation is my favorite :3
Keiji and Mitsunari, I prefer the former partly due to his story being much more substantial and the general badassness of carrying a giant nodachi one handed. hes strong and got some good moves that are really quick for a sword of that size. his specials arent the best, but i think its pretty convenient to just drop down somewhere and regain ur health lolz. Mitsunari. Fast, strong, racks up huge combo counts. just a generally good character, though his defense needs a bit of buffing up though. got some pretty badass specials too (decapitation comes to mind)... those are the two i've maxed and found all fugitives for, though i havent unlocked like 6 characters yet and also not Pirates at Noshima, Siege of Kanegasaki, and Honnoji. Oichis pretty good too.
"Better that I betray the world than let the world betray me!" -Cao Cao, Romance of the Three Kingdoms.
Kotaro, līm untouchable with him, l mean, l got most of the unharmed materials with him, besides, l like the badass feeling of fighting airbone for pretty loooong periods of time, specially on hard. l find his cancels pretty creative even those that can be done mid-air with his regular s-string.