I case anyone is still thinking of getting the Sierra 2's, I'll add my two cents. I've had mine about three weeks, and am very impressed. Right off the bat, I thought they seemed a little bright, but either they've calmed down after burning in, or my ears have adjusted. Part of the adjustment is that they just give you gobs of detail. Probably a little of both. And the bass response in tight, and tuneful - and plenty for me. And probably my favorite thing is they sound fantastic at lower volumes, as I live in a condo.
Associated equipment:
Rega Elex-R amp
Mostly lossless digital files (some 320) from either my iPod classic, or computer.
Peachtree DAC
Highly upgraded Rega RP3 w/ Rega Exact and Rega MKii Fono amp
Speakers I've either owned or auditioned in my home in the past few years:
-Monitor Audio GR10 - pretty amazing paired with a NAD 326 amp - fantastic bang for the buck.
-Epos Elan 15 - seemed kind of dark - didn't keep for long
-Monitor Audio GX100 - nice, but always sounded like you were listening to a speaker - not very transparent.
-Totem Acoustics Rainmaker - way too bright with my amp.
-B&W 685 S2 - Great bang for the buck - great with digital music, but I didn't care too much for them with my vinyl - a little too warm.
-Dynaudio Excite X-12 - the best I had until I got the Sierras - great imaging, tight, punchy bass, and good detail in the highs.
-Dynaudio Focus 160 - hands down the best tweeter (but the Sierra's is very, very close), but the bass response seemed kind of flabby and unfocused.
And it certainly doesn't hurt that the Sierra 2's are drop dead gorgeous. I got the B-stock satin espresso, and I have no idea why they were b-stock, because they look flawless to me - and I saved $300.
Hope this helps anyone else thinking about getting a pair - I think they punch way above their weight.