I don't think Irwin makes anything in the USA anymore.
The description on Amazon says the C-L set is "Made in the USA".
Since I don't know your definition of "deal", my best answer is I would buy the C-L.
C-L is a long standing USA company with a good reputation, IMHO.
Thanks guys. Despite only using wire size bits once in a blue moon (when only that size will do) I went ahead and spent the extra for the C-L bits. They are 50% more cost but the stub length just works better with tiny holes. I doubt in my lifetime I will drill enough holes with any one bit for the quality difference to become an issue.