If I understand both correctly, the Quantis one generates a random number that didn't exist before generation due to quantum measurement principles, whereas the Simtec one uses a high noise environment in which the number does exist before measurement.
You're repeating nonsensical marketspeak. What does "a number that didn't exist before ..." even mean? And what does "quantum measurement principles" mean? I'll tell you: it means diddly squat.
The device the article is about measures electron flow through an electronic component through which 'usually' no electrons flow. That electrons flow in this device, is because they tunnel through the potential barrier. That's a quantum effect if there ever was one.
Converting the presence of electron flow into a number means you construct these numbers on the fly. The numbers did not 'exist before', for any reasonable meaning of that term.
Acutally, Simtec states: "each 256 bit block of data handed to the host was formed from somewhere in the region of 3840 bits read from the quantum generators."
Yes, you can buy "quantum generators" for only £36!
Seriously though, the noise that Simtec is measuring is unpredictable and based on a quantum process (electron tunnelling.)
If I understand both correctly, the Quantis one generates a random number that didn't exist before generation due to quantum measurement principles, whereas the Simtec one uses a high noise environment in which the number does exist before measurement.