It's been almost three months since I received by Sierra Towers (w/ RAAL) and I've had a lot of listening time with them (at this point they're fully broken-in...I noticed improvement until about 20 hours, no change afterwards).
I am very happy with them in my stereo-only setup (a mixture of old and new devices for inputs, amplification, etc.). The sound is very neutral and the frequency response is excellent (well, as good as my 60+ year old ears can hear at the upper end, and I have a nice PSA sub for the very bottom end) -- it appears to be as razor sharp as the chart that came with the speakers indicates.
I chose these over a number of other top brands (B&W, Focal, Golden Ear, Revel, etc.) and I had the opportunity to listen to them all in my listening space and compare them pair-wise. While I thought the Sierras sounded better than any of the others (although it was very close in the case of a couple of other speakers), given that they were less expensive than any of the competitors I listened to they were a fairly easy choice.
I would recommend them highly to others thinking about speakers in the $2,000-$4,000 range -- or at least give them an audition as we all hear differently.