What actually happens is that there are three levels, but those levels are divided into two sub-levels.
Thus, there is low 1 and low 2, medium 1 and medium 2, and high 1 and high 2.
A quick double click switches between the two sub-levels.
A slow long press gives low.
A fast short press gives high.
Holding the button down ramps from low, to medium, to high, and this cycles over and over.
Most of the time, flashlights are used on turbo, or low; medium least frequently, for most people.
The actual sub-levels are remembered by the flashlight.
So if you were previously on sub-level low 1, then it will turn on at sub-level low 1.
If you were previously on sub-level high 2, then it will turn on at sub-level high 2.
So the actual sub-level is remembered.
A quick double click switches between the two sub-levels.
The only problem with the SC600 is that not everyone wants a 30mm bezel diameter; some may prefer a smaller 1 inch 25mm bezel diameter.
Also, the usage and timing of the button takes a while to get use to.
Even after 10 months, I will occassionally accidentally turn my SC600 on turbo 750 lumens OTF at 3 am in the morning just out of bed!
Hence the SC600 is not the finest bedside light; it is better for medium distances like the back yard etc.
I just purchased a Jetbeam RRT-01 which should be perfect for the bedside, with a continuous adjustment ring, and a super low low, but only 500 lumens...