I finally finished the review of the Sola ENG for Creative COW, including an audio recording of the Sola's fan. Overall, the light's power and focusing quality are really helpful, as is its fairly low end energy requirements. But if you shoot in quiet spaces, or with an on-camera mic, you may have problems with the Sola's fan noise.
My take was that the Sola will be useful to a lot of shooters, but most will run into a situation where they wish the light wasn't quite so loud.
Also, while fact checking with Litepanels, I learned that they actually plan on selling a modified version of the Sola fairly soon, which will make it easier to run the light off other batteries, versus the current D-tap source.
You can see the review here.