I thought my Sierra-1NRTs were amazing, they were a huge amount better than the Mirage towers they replaced. After comparing the Sierra-1NRT, and Twos it was readily apparent the new speakers trumped the already fabulous originals in every area. Accuracy, linearity, and transient response all perform at a higher level than my NRTs.
I must also mention that after having listened to my RAAL equipped Sierra Towers/ Horizon for quite a while now, I'm spoiled with the high end the ribbons provide. I don't think I could ever be happy again with a dome type tweeter, the RAALs really are exquisite! Even with the Sierra-2s used as surrounds, with multi-channel surround music, the difference is quite noticeable on some material.
I think that anyone buying the Sierra-2s for a movie set-up will probably end up listening to a lot more music through them. Also, they will likely be looking for high quality recordings, because these speakers just sound increasingly better with the quality of the source material (and conversely, poor recordings are stripped bare as well).
Jay