I compared the kicker core and the PP5.
After an 800W sprint, there was a slight offset change, but it wasn't significant on mine. It was around 2W, and it didn't seem to accumulate.
At around 14 minutes, I set the kicker core's rolling resistance to maximum and pedaled with my body weight. The cadence was so low that the wattage wasn't displayed, but a significant torque load was applied. However, there was no significant offset change after that. In fact, the two graphs became almost identical.
At around 17 minutes, I set the kicker core's resistance to 5% and manually rotated it at 130 RPM in the innermost gear. If there was any residual stress within the PP5 (meaning the sensor compresses when pedaling and then recovers slowly), I should have consistently seen +20~30W(for example). Since it consistently showed less than 10W, I don't think the phenomenon of overpowering higher than the kicker core occurs often. (This kind of empty pedaling can be used occasionally during a ride when you're suspicious that your power meter is displaying inflated power.)
It's true that Chinese products have poor quality control, but mine seems quite well-made.
I bought the aluminum crank arms and power meter spider for $80.
I plan to move to Assioma after achieving FTP 4.0 on PP5!!
I used a machine translation, so my speech sounds unnatural. Sorry ^^