I have eaten both BRs and BOs. They are comparable. Both eat like dual purpose chickens, not like CXs. Mostly it depends on age as to how tender they are. Older birds, especially mature roosters, taste best when used as a soup or stewing bird. They are delicious when cooked this way because they develop more flavor as they age but lose tenderness. I am raising a new batch of colored range broilers aka "freedom rangers" but they are only 7 weeks old now. In a couple of weeks I'll begin to process them and I'm eager to see how they compare. I've also raised and eaten Dark Cornish which have a noticeably larger breast than the BOs and Brs, but taste about the same.
I think all these breeds are fine dual purpose birds, just don't expect the breast meat and tenderness of commercial CXs.