sCMOS 5T pixel has two transfer gates per pixel (problematic architecture considering the possibility of PD-to-TG barrier mismatch between the two gates):
The chip architecture looks like two vertically mirrored sensors on a single die:
There is a very nice graph showing regular sensor's advantage over electron-multiplying detectors, such as emCCD - no excess noise at higher light levels:
Overall, it's a nice and easy to read marketing presentation with light technical content - recommended.
Update: As mentioned in comments, there is a recent Photonics Spectra article comparing EMCCD with sCMOS "EMCCD vs. sCMOS for Microscopic Imaging" written by Photometrics, Arizona-based supplier of CCD cameras. It's interesting to see their comparisons to be somewhat similar to PCO's.