Well I just got around to installing a pair of Sierra 1 NRT's as L/R. These are replacing an old set of Wharfedale speakers and I have to say that I'm very impressed by the sound that they put out.
They are being driven by a Yamaha Aventage A-1020 receiver and so far so good. I have a Rhythmic Audio LV12R sub that I will eventually pair them with however even without the sub and without running the YPAO setup on the receiver I'm plenty impressed with the speakers. The bass from these speakers is quite incredible and I love the sound at the highers end of the spectrum as well.
I'm looking forward to calibrating the speakers for my room and optimizing positioning so that I get the best sound possible from these beauties. I spent a long time researching what speakers I should buy and I have to say that I'm not disappointed by the Sierra's in the slightest.
Thanks Dave for manufacturing such a superb set of speakers for the price. I think that they would be a bargain at double the price and the fact that I bought a used pair that were 50% of the current retail cost just makes it all the better!