This question quotes Terry Pratchett's claim:
The British resisted decimalized currency for a long time because they thought it was too complicated.
Is this a fair comparison with its inference that British currency was significantly more complex than decimal currency?
Or is it a simple matter of lack of familiarity leading to misunderstanding?
For purposes of comparison, even though it is a century earlier, the era of interest I believe is best taken from 1800 to 1850, early to mid 19th century. Both the U.K. and U.S. are then on a metallic currency standard, and the smaller coins in both currencies still retain real buying power. I believe this provides a better comparison than latter time periods, say after the Second World War, would.
Although I have posted an answer below, I have no intent to accept it. The material there is posted as a resource for any and all who would care to attempt a definitive answer.
GO FOR IT!