The difference with APA102 and APA102c
There are two versions of the market, the APA102 and the APA102C, as shown below.
The APA102C comes in a package very similar to the WS2812, while the APA102 comes in a package with an increased metallization area to improve heat conduction. The APA102 is more expensive, possibly owed to the more complicated package. So far, I was only able to investigate the low-cost version, the APA102C.
The picture above shows the current modulation for RGB=255,255,255 and the global brightness set to 16 (50%). The pulse width modulation is clearly visible in the voltage signal at a frequency of 580 Hz, very similar to the 430 Hz of the WS2812.