Russian Circles are pretty good, but I have to say I found their debut album more original and enjoyable than the following two. They're all enjoyable, I just found the last two a bit on the boring side I guess, compared to the first.
I agree some of the bands you mentioned are post-metal, but would you really consider Russian Circles post-metal? I guess I just don't see them as being that heavy. Not that they're pop, mind you.
I guess they could just be seen as either post-rock or post-metal, kind of straddling the line I suppose. I think it's because I typically associate post-metal with a bit of sludge, which I don't hear in Russian Circles.