The collar with the button on the back of the neck is silly. What is that an attempt to make a fashionable collar?
2) Red Fleece is BB's pathetic attempt to eat into J Crew's ownership of non-greybearded shopper (i.e. the younger demo).
As far as your original question, there possibly may be no difference at all between them; for all we know, they may be outsourced to the same factory in China.
I don't particularly prefer Red Fleece but they're the right fit for a guy that's thin with long arms. Most sport shirts from other makes have 34" sleeves for size medium but RF appears to have longer sleeves which fits me better.
But you're right they're all made in China and likely from the same factory.
Probably now that you mentioned it! The styles are so similar. So where do you shop for casual shirts under $50?