Adam Hall 87451 Smart LED Rack Light

When I connected it and tried to push the on button, it didn't do anything. It was just stuck. Considered sending it back, but thankfully it looked like everything could be opened quit easily, and it was. 4 screws for the plexiglass cover, 3 for the board.

Once out of the case (still hanging on with wires to the power input in the case.. be careful not to break those), the button worked fine! So I took some very rough sanding paper and sanded the hole for the button to be slightly bigger.
Reassembled everything and now it works!

The motion sensor is a bit disappointing to me. you really have to move on the right side just below the light for it to work, but workable for me.

The light goes straight down, so if you have a big number of units, the light might get blocked by knobs on your other gear. For me, after 5 units it starts to fade and become less useful. Consider putting the units needing the most light the closest to this unit. I expect that for a large rack a gooseneck variant would have worked better.

The light quality is excellent, these things do what they advertise.
Lost one star because the motion sensors are too insensitive for me, I have to wave my hand close to the light to get it to respond, and I would have preferred a totally-off motion sensor operation to settable brightness to this full-power-on-to-settable brightness, which gives a distracting flash of cold light in dark venues, so another star for that.