I agree with almost everything in this book, in fact if I were more intelligent I would have written it! Having said that, there are a few things I take issue with him on:
Intellectual property. Kurzweil says that as technology progresses, more things become information. This I agree with, but he goes on to say that it is important to protect the information so you have money to create new things. Here he's trying to perpetuate the idea of intellectual property. I believe that information can't be treated as property, and should be released as free content. You may then ask, how do you make the money to build new things? Well, free content is often available for no charge, but most of the inputs to creating knowledge is other knowledge, so substantially less money would be needed. Okay, but where do you get the small amount of money that is necessary? Well, advertising is the popular method. I'm sure Wikipedia could make an enormous amount of money if carried advertising.
Consciousness. I'm pleased that Kurzweil devoted some of the book to the problem of consciousness. Unfortunately nobody understands it yet as far as I can see. I think Kurzweil accepts that it is essential for our post-biological successors to be conscious. So until we understand consciousness and can recreate it artificially, I think it's difficult to make predictions.
The structure of society. Kurzweil quotes Hobbes, 'the life of man, solitary, poor, nasty, brutish, and short' to support his case that improved technology leads to a better standard of living. But Hobbes wasn't merely talking about technology, he was describing life in an unstructured society, an anarchy, or what he called 'the state of nature'. Hobbes' point was that for life to improve and for technology to develop, a structured society is needed.
So I'm disappointed that Kurzweil does not realize the importance of the structure of society. Indeed, Kurzweil talks of the military applications of nanotechnology, but this is like our ancestors talking of how in the far future, technology will be used to defend our village from attacks from other villages. Thankfully we have national Leviathans in the form of democratically elected governments that means that each village doesn't have to defend against its neighbouring village. I predict a global Leviathan, a democratically elected world government, so that countries don't have to worry about defending themselves against other countries.