Having bought this book and reading it currently, i thought I'd chime in:

Overall, a pretty decent read so far. Walling makes a very, very strong case for marketing as an essential arm of entrepreneurship - something I was honestly content to ignore till now. He also underrates the act of development - whether this is what he genuinely thinks or an attempt to off-set a natural bias in his reader, I am not sure.

Definitely worth a read, but I am not happy to see the price at $19, when I bought it just a couple of days ago at $24. You listening, Rob? :)