For me, Chairs still has been the most obviously scummy person... he's done quite a few things that have raised alarms for me. He's been overly agreeable, in the sense that he's changed views because others have asked him to (Posts #219, as one example, and also reminding us that he agreed to not no lynch because that's what we wanted), threw out a bunch of vague scumreads without initially backing them up, only backing them up when asked, finding a player scummy for something from outside of the game, etc. Had any other player been doing the things Chairs did, I would find them very scummy. BUT, chairs is a new player, so it is not necessarily as revealing in this case. I still have my suspicions.
I don't at all buy the case on Yuma. From my point of view, Yuma's doing things that both scum!Yuma and town!Yuma would do... how in the world are you supposed to determine if he's scum or town from that? I have a very difficult time reading him, but nothing SB or Voltaire has said has convinced me he's scum instead of town. I just have no clue at this point.
I'm reading SB as town. If you go back and re-read the initial game with the thought "SB is scum", there are a number of posts that jump out at me as "oh, that makes sense". I tried reading the new game with the same thought, and didn't come up with anything that would make sense as him being scum. Maybe he got better with his quick practice, but I'd guess he's just town.
I'm not sure what to think about Robz. His main view so far has been heavily pushing the chairs=scummy view. It could be true, but I think it could easily not be.. I have no read on Robz at this point though.