I read Isaacson's long-ago book The Wise Men (written with a coauthor) and found it masterful, engaging, and comprehensive.
One of Siracusa's main objections to the Jobs bio is that Isaacson does not understand technology enough to separate the important from the trivial.
Isaacson has faced this kind of problem begore. It seems from this review that he had advice from Brian Greene on his Einstein bio:
http://www.nytimes.com/2007/04/09/books/09masl.html
I wonder if Isaacson did not have enough help with the tech on the Jobs book?
Siracusa pulls no punches and each and every one of his criticisms is well thought through.