I think their music is pretty good if you like the post-punk pop genre. As for their politics, it’s pretty much what I would expect from a bunch of Gen-Xers from Berkeley. Shut up and sing.
As a classically-trained musician who (openly) likes pop, I try to be objective:
I think they are above average, but just so; I never thought they were extraordinary, even assuming one likes that genre (which I mostly do not).
I think their flaming leftism garners them more acclaim from communist critics than they deserve.