I used the Combo updater while in Safe Boot, and by far, this is the smoothest (and fastest) OS update I've done in years.
At the conclusion of an OS update, I always run DiskWarrior, and it always finds assorted things, nothing serious (I think), merely a few errors. But this time, DW found only 1% of what had been my norm, leading me to conclude that DW doesn't work as it did with previous OSs, or this update is vastly improved.
FWIW: my results were practically identical on a 27" i7 iMac and mid 2011 15" MBP
