I know the GM BK well. On the GM BK the creditors got about 10 cents on the dollar. The government really screwed them! They gave what should have gone to the creditors, equity in the newco to the UAW. I don't recall if there was any preferreds other than exchanged traded debt.
I did okay on the bonds. I bought at about 5 cents on the dollar. But, I expected much more and never expected the government to gift shares to the UAW over the creditors.