No difference between preferred and common?
It would be very illuminating to understand your reasoning for this statement, when a comprehensive review of the facts shows it not to be the case. The junior preferreds are superior to the common shares in the capital structure of the company and consequently are less risky/more likely to get paid out in the event of a complete wind down. This explains the price discrepancy- people pay more for safer investments and in turn must be paid more for risky investments.
Truly, one must look at the source of the information as well as the 'information', because people often have very different goals.
Even if the companies are completely taken apart, Uncle Sugar is going to by law owe me $25 each for my CKJs.
I owe common too, but have much less invested there.