First review from the top.
"I bought this book thinking it would be thoroughly, if not exhaustingly, researched. I was terribly disappointed."
The critique I chose was overwhelmingly negative in regards to the book's execution and specifically the lack of empathy/effort/research put in by Barbara Ehrenreich. Whilst the review is void of quotations from Nickel And Dimed the complaints are still valid if viewed as being levied against the book as a whole (and because it was on Amazon.com the conduct of reviewing books is populist rather than professional). Personally whilst the review is skeletal (which in my opinion helps it get to the point) and lacking in direct literary quotations or criticism I do agree with the author's ("A Customer") sentiments.
As mentioned the key aspect of A Costumer's critique is that Ehrenreich was very lazy in the conduct her project ("Each [job] lasted no more than a month."), failing to delve deeper into the mindset of a person on the minimum wage and subsequently live like them ("For instance, she never shopped at yard sales or second-hand stores"). On both of these aspects I agree with "A Customer" I felt that doing three months (divided into three places) of being "Down & Out" were woefully insufficient to really give a good insight to life on the bottom rungs. The fact that she also had her safety net of $1000 and a car didn't help matters; so many times when reading I felt Barbara should have just roughed it out a little more, spent maybe a year, even two living below the poverty line, which would have been far more scientific and accurate in gauging minimum wage life. I felt that Barbara just wanted to get the project over with as soon as possible to return to her comfortable life-style.
To further his argument "A Costumer" gives a short life story describing how he (or she) came from a minimum wage family and was "the first in my family to attend college". Whilst this segment initially seems to be a attempt to garner sentiment for the review it goes on to point out that "A Customer" worked the minimum wage life and "went on to higher paying jobs". Of course this part of the review may have been fabricated to add legitimacy but I doubt it, as it stands however, it does show that the reviewer has experience in the life Ehrenreich tried to replicated and so he would have a good perspective on her failings. However one could argue that because "A Costumer" is so deeply connected to minimum wage life he or she lacks the perspective to the large picture, I do not think this is the case.
"A Customer" then points out that s/he agrees with other Amazon reviewer's opinions that Barbara looked down on her co-workers, "they were stupid drudges, victims of the system and selfish affluent people" and that she (Barbara) wrote herself as being 'right' ("but - not to worry - enlightened Barbara to the rescue"). Here I can only partially agree with "A Customer"; whilst there are occasions where she (Barbara) looks down on her co-workers most of her negative sentiments are against the system and the corporate bosses, whilst she does occasionally portray her fellow workers as simpletons she always makes them sympathetic characters.
Finally "A Customer" says that the book had potential but failed because of "A Agenda", unfortunately she does not elaborate on what Barbara Ehrenreich's "Agenda" is but I imagine it was to shock and spark debate. "A Customer" declares that the book failed to do that but I disagree, Nickel And Dimed, whilst indeed very flawed for the reasons given (and they are good reasons) it has sparked a discussion about minimum wage, much in the same way Upton Sinclair's The Jungle sparked discussion about worker safety in the meatpacking industry, though shock value, Which is ultimately what I feel was Ehrenreich's intention.
So in conclusion whilst I feel that "A Customer" makes very good criticisms that I personally agree with they ultimately are unimportant because the book was designed not to give a scientific account but rather a populist and easy to read article to push for worker rights. Something I agree on.