This is a tough one because I actually think the York branch (other than Richard III) were more sensible. On the other hand, the Lancaster dynasty were more legitimate in the sense of direct descent. When Henry Tudor took over England after the Battle of Bosworth Field, he had the support of those who had backed the by then extinct Lancasters, as well as some Yorkists who didn't like Richard III. Tudor himself was descended from the Lancasters, and married Richard III's niece. This created one of the most stable and even peaceful times in English history.
I basically agree. This is a tough one.