Observations on plant growth
It grows plants well generally. This is especially so for the area directly under and +2 inches from the radius of the fixture where the PAR values are very high. Strong coloration in red plants and light demanding plants on the substrate level grow well. Eriocaulon quinquangulare and Trithuria lanterna grow well in this layout even with partial shading from hardscape / taller plants.
The only downside of such style of fixtures is that tall plants on the left and right wall get significantly less light than the middle. This is in contrast to fixtures that run the entire length of the tank, which gives more even lighting overall. It is possible to mount such lights higher to get more even coverage, at the cost of losing PAR in the center area. I chose to mount it lower in this case (6.5 inches off rim) so that there is higher PAR in the center and less light spill outside the tank. Generally not much light spill for this fixture.
PAR and spectrum observations
These readings are taken when the light is running on maximum power. PAR in the central area (within the foot print area directly under the light) is around 100+ on the substrate (4 inches thick or so) and 300+ just below the water surface - this is with the light mounted 6.5 inches off the rim of the tank. Direct beside the front glass the PAR rises to 150+ due reflection off the glass (typical for most lights). However, at the top left and right edges, the PAR dips to around 50 - 60+ range. As mentioned above, one can even out the difference by mounting the light higher. Most folks would probably choose to do this as most tanks can do with less PAR in the center area.
Generally, the fixture produces very high light levels when compared to other common consumer planted tank lighting systems. This allows for great plant coloration and higher density for plant bunches. Compared to point source lighting (i.e. kessils), there is not much noticeable shimmer. The plus side is that because the fixture array is not too small, light is generally well distributed - areas beside hardscape still receive adequate lighting.
One odd downside to this fixture is that it flickers at a rate that is undetectable to most human eyes, but is apparent sometimes on a camera. If you have super sensitive visual perception, it may be an issue. I do not sense it when looking at the tank, but I can sense it when I stare at the rippling water reflections off my wall.
The spectrum has high red/green/blue saturation that highlight these 3 colors. This is great for folks that specifically want red / green highlights in their tank. The overall visual presentation is attractive - with a tad "cool" color temperature hue around 7000K +. The only downside of this spectrum profile is that near-red coloration such as purple plants, will look more reddish rather than purplish. Orange sand may also look reddish orange rather than orange. Similarly, the difference between different green shades are is less distinctive (slightly) compared to lights with a wider spectrum profile. This is the typical trade off for light systems that specifically highlight certain colors (red/green). I find that most consumer will be happy with the contrast though - that is why lighting systems such as the ADA Solar RGB are popular. Relative color accuracy takes second place to saturation and contrast in overall tank presentation / visual impact for most folks.