The Sierras are a great speaker,
the only thing I did notice, but have no real data to support it, is when I was running them full range, they use a lot of power when making bass, I only noticed this because when they reproduced any bass notes the lights on my xpa2 shot higher than I ever seen them go so I kept the volume the same and plugged one of my 40 towers into one side and kept the sierra on the other, and sure enough for some reason the sierras made the amp lights go higher which makes no sense? {so I figured maybe this was because it was stereo and they arent identical signals so I used a y and gave both channels the same signal, still offset to the sierra, so I swapped sides, and the sierra still lit more lights on the opposite side, I don't know what caused that... But I did run them crossed at 100hz and they lit the identical amount of lights as the towers... Weird...
but anyway, that is useless, the seirras sound good, I would definetly look into them, and sales never hurt, plus if you buy now, for a year, you can trade up with ascend and get full value for your sierras!!!!