Am posting this from my aluminium mid-2009 MBP, it worked fine.
Did my MB Air earlier today and it went fine too, except for the iTunes 12 update to 12.0.1 which forever kept showing as an app for download. I downloaded it four times before I found the solution (google

) which was to go to the iTunes site and do a manual download.
All working well all round so far. Haven't done the iMac yet as it is in another country.
It took hours for each one as my download speed is about 5MBps!!