Caught up on Obi Wan today. It's pretty good but personally I don't like the idea that Obi Wan and Vader had an encounter between the prequels and "A New Hope". I think it really takes away from the gravitas of their final encounter on the Death Star. I like the idea of Vader obsessively looking for him, I like Obi Wan being traumatized by everything that happened, and his reaction to finding out Anakin is Vader, etc. I think it would have been better if Obi Wan never actually encountered Vader directly in the show though. The scene where he is hiding and Vader is raging around killing people is far more interesting than when they actually confront each other.
Third Sister is not a good secondary antagonist is the only issue with that obviously. Like YNA said she's getting a lot of totally unfair racist attacks so I don't want to be too hard on her, but she really isn't a great actress or at least the material isn't giving her a lot to work with. The kid playing Young Leia is pretty good, and shows that you can actually have a tolerable kid actor in Star Wars.