I've generated three worlds on default settings - so 100% ore "concentration."
In each of them, I've propick sampled literally hundreds of chunks across tens of thousands of square blocks of area and never seen anything above "Decent." Rarely can I actually find a deposit using the other propick mode, even when spending hours looking.
Additionally, I can be in a mountainous chunk looking up at a giant quartz deposit, and quartz never shows up on the propick output.
Am I missing something? Does it really take DAYS of gameplay to find single deposits?