Actually, I believe all the original S6 episodes are on YouTube, and the only redubs on there right now are "Sue Ellen Gets Her Goose Cooked" and "Best of the Nest". Netflix had the redubs until recently when all the Arthur episodes they had available before S13 were removed.
Anyway, this is my personal ranking of Arthur's voice actors (not counting Carr), from favorite to least favorite:
Michael Yarmush (1-5)
Mark Rendall (6 redub, 7-8)
Dallas Jokic (12-15)
Justin Bradley (6 original)
Drew Adkins (16-)
Cameron Ansell (9-11)
To me, Cameron Ansell sounded like he had a cold half the time, especially whenever he said Buster's name. I can't stand hearing him repeatedly say "Hey, Buster, let's play some ball." in "Flaw and Order".
I actually didn't know Arthur's voice in S5 was still Yarmush until recently. Not too much of a difference in pitch between that voice and Bradley, though Bradley always sounded bored and wasn't nearly as good an actor as the others, and his voice was sometimes prone to cracking (such as when he says "I don't know what happened" at the beginning of "Citizen Frensky"). I never really minded the deeper voice Arthur had, though I much prefer the redubbed S6 episodes to the originals. When they were on Netflix, I'd compare them to the originals on YT and Rendall delivered every line better than Bradley.
It's nice that Yarmush still works on the show as Slink, and his voice has been kept in the opening. And even after he stopped voicing Arthur, sometimes audio samples from him like his grunts, laughs, and sighs, were still recycled, though not anymore, I don't think, and sadly, the famous "Arthur gasp" used in many of Yarmush's episodes was never re-used after S5.
I think they should have kept using it because it sounds that hilarious.