I first became aware of the series when I was attending a couple friends' wedding at Disney World in 2014, but I never watched it except for some YouTube clips. From what little I know of it, it seems pretty cool. For example, it brings back into canon the Inquisitors, Imperial Force-wielders who use the Dark Side to hunt Jedi and enforce Palpatine's will.
(I didn't agree with junking the entire Star Wars Expanded Universe, but this does show that Disney is willing to bring back into canon the good parts of the EU. After all, what's the point of being a Sith Lord if you're not lord of something? Just a single apprentice doesn't seem like much.)
Vader facing off against his former apprentice looks to be poignant as hell, not just due to the relationship they had before as seen in the clips but also due to the obvious pain the situation is putting Ahsoka in. See the clips below:
I'm not sure if I'll be able to watch it when it comes out, but I'd definitely like to see how this shakes out. Given how Ahsoka is never mentioned in the original films I suspect it won't end well for her, but it could be a lot of fun to watch.