I have never used the Solar I, but to me seems like outdated tech these days. I do have an aquasky over my 30c and love the color rendition and the lush healthy growth. Since switching the tank has become one of my favs and looks fantastic. I really can't say anything bad about the aquasky. In fact, if ADA ever releases an LED for larger tanks like a 90p I will be chomping at the bit to get it.
I think somewhere that ADA said the Aquasky 602 is comparible to a solar I. I can't remember where I read that... one of the aquajournals, I guess.
I just ordered the aquasky 401 so can't comment on it yet, but I have used a Solar I and I LOVE it. I am sure I will love the Aquasky as well.
What I don't like is that the Aquasky can have a color temperature of 7,000 to 8,000 Kelvin... that's a lot of variation. Also, is that per LED or per unit overall? ADA doesn't say. If it's per LED it shouldn't matter but if it's per unit overall, that could give a noticeable difference in color if you have two units side by side.. one could be 7,000 and one could be 8,000!
The solar I gets HOT and uses a lot more electricity. The lamps need replacing about once a year and are about a hundred bucks each or so.
I do like the more open feel of a hanging metal halide. The aquasky looks boxed in, but thats just personal preference. The solar I units are very heavy and built with a lot of quality, and if you need to you can easily raise or lower the fixtures. The aquasky units can't really be raised or lowered unless you want to DIY some sort of hanging device. The actual light is removeable from the acrylic stand.
If you want a 60-P, get an aquasky 602or a 602 and a 601 for extra light. A 601alone would probably be the equivalent of a grand solar II.
I'd love to know the PAR given off by the lights. I think ADA has only released the LUX info.
one thing I like about the aquasky is that if you scratch if for whatever reason, you can buff it out since it's acrylic.