I have three Sola ENG's that I have bought over the years since they introduced them and I bought the three light flight case kit(for a total of six, now) back in November. You can hear the fan in a VERY quiet environment with your ear close to the fixture, but I've never heard it on-camera. I also have an original LP 1x1 daylight and just received two Astra 1x1's last week. I love the Sola ENG's. I do have some issues with their design that really bugs me, but the quality of light is great and so far has out weighed the (in my opinion)design flaws. The Astra's are really nice. Bi-color and a lot of punch. The power set-up is in-elegant and janky as hell, though(can someone tell me why they decided to use a THREE pin XLR for power?). And the overall design I think was penned by Fisher-Price, But again, good light(you will need some 1/8 minus green if you use them with legacy 1x1 LP panels, though). They also take up a LOT of room because of the design of the yoke. The PortaBrace case designed for two of them still hasn't shipped yet, so the only case I had that would fit them was a Pelican 1650. Yes, I had to put two 1x1 LED's in a 1650…
I did National Signing Day on Wednesday(all Live and/or 60P 'video') and I used the two Astra's as keys, a Sola as a top light like always and used two Sola's for the background when they shut the studio lighting off. Everything looked great. There was tungsten and flo's in the room/studio also, but all of my lighting that I set was LED.
Fast forward to today and I was shooting sit-downs in 24P. All tungsten. I'm not getting rid of any of mine. In fact I just added another Source Four a few weeks ago.
Different tools for different situations.