I have read only few series of Superman: secret origin because it seems to be repetition and has been done so many times. The work of Grant Morrison’s one page origin is All-Star Superman is very much sufficient for me.
I am not the regular follower of all Superman issues. I missed Kurt Busiek retooling Superman but I have read different series of Superman’s origin. Superman has a long history and we can let it be without “retelling” and “reboot” of the origin.
The art work of Gary Frank in Secret Origin is phenomenal. Clark Kent was good to see acting like Christopher Reeve. This characterization proved to be show stealer. It is to be understood that Secret Origin is tremendously entertaining and their pacing is good in mini-series
While looking at the other side of Secret Origin, I found that there is no any secret in the whole story. Only by careful notification I guess there are only few changes in the new series for just continuity.
Superman will be a good addition for your comic library. But for me- a great fan of Superman issues- it is little bit down to expected level. Except Gary Frank’s marvelous artwork, I think Geoff Johns work has proved better.