Some further elaboration...
Boulder bass command and power is the likes of which I have never heard. But the bass resolution and nuance seems better on the Soulution. *Note that I am comparing the 3060 to the 711+ and not the pair of 717s on order.
Boulder transient detail and speed is amazing. But also somewhat granular - even fatiguing at times. The Soulution not as quick but more pleasant.
The Boulder is an equal opportunity resolution amp - meaning that sometimes very subtle or delicate cues can get over resolved (or so it seems). The Soulution seems to do delicate better.
Soulution air feels more organic than the Boulder.
The Boulder takes absolute command of the speaker. As such, instrument decay often feels artificially cut short or muted.
Overall dynamics on the 3010 are better than I have ever heard on a pre-amp. But, it is quite dry. By comparison, the 727 has a touch of warmth and pleasantness.
Density is an interesting one. On lower frequency dominant tracks the Boulder seems a bit more present while mid-range and up dominant tracks come to life with the Soulution. Vocals are simply more real on the Soulution.
The Boulder and the Soulution are both AWESOME. Like most of the high-end gear it comes down to personal preference. For me the choice was an expensive one. I sold the Boulder 3010 and 3060 at quite a loss to get the Soulution. Not once have I wished that I made a different decision - love the Soulution gear. Now if I can just get the upgraded 717s! Did I mention how anxious I am to get the new 717s...