It is interesting to speculate what the EC4S will offer. Its cousin, the EC4, has 5 output levels. The manufacturer's ratings (in lumens) for the EC4 are: 1, 80, 240, 520, and 1000. Spacing is not too bad, but it might be nice to have another level, around 25lm, squeezed in there. Something like 1, 25, 100, 240, 520, and 1000 might be ideal.
What will happen if the EC4S goes for big output? The P36 drives the MT-G2 to a nominal 2000lm. What mode spacing would Nitecore offer if it drove the EC4S to a similar level and used a similar interface, i.e., one that has only five output levels? Whatever answer you give, the spacing would not be nearly so nice as the EC4.
That's the problem faced by the designers of the Fenix TK35UE. To make things worse, the Fenix designers limited themselves to only four output levels. For the TK35UE, they chose (in lumens): 25, 250, 750, and 1800.
This is one place where the Nitecore P36 really shines. Its ten output levels—as rated in lumens by its manufacturer—are: 2, 20, 80, 210, 380, 600, 850, 1100, 1500, and 2000. This is very nice, even when you factor in Selfbuilt's lower estimate of 1850 lumens for the output on maximum. The key to this is Nitecore's mode dial. Selecting output levels could not be easier.
For what it's worth, all three flashlights, the EC4, the P36, and the TK35UE, decline from their maximum output level in a matter of minutes. More interesting is the output levels they can maintain—without stepdown—over a period of hours.
I am eagerly awaiting the EC4S. It is decidedly more coat-pocketable than the P36, and it might even be small enough for EDC if stowed in my daypack.