I have been a dedicated Mac user since 1991 and the turn around that Apple has pulled off never ceases to amaze me. Look at the OS distribution of readers of NephJC.com. Apple has 59% of visitors between iPhone and MacOSX. Incredible.
But I don't think all of the credit can be given to Stevie J and his merry band of Nexters. Look at the twin debacles of Vista and Win8. Together, those two OS's can't smell the OS share of XP whose latest update was over 6 years ago!