The book also just not outstandingly written. The first half is also stuff that's pretty much known from other books or sources, so if you've read a lot about Apple or Steve Jobs, there's nothing really new.
I'm just speculating, but maybe that is the reason why Jobs chose Isaacson.
In the same way Apple products are designed not for nerds, but the "rest of us", perhaps Jobs wanted the same for his biography.
Hypercritical 42 - http://5by5.tv/hypercritical/42 The Talk Show - http://5by5.tv/talkshow/66
Careful when you listen... the entire network of podcasts is highly addictive (if you're into podcasts).
It's slow moving, but once Siracusa gets rolling, you can taste his frustration with the crappy job that Isaacson did with it.
edit: typo.