It is ultimately the quality of the book that matters, obviously. I always use amazon reviews to judge if I should buy a book or not. I rarely care who the publisher is. Obviously though, the marketing that goes into a book from a big publisher will be better advertised and so there is a much better chance that I will have heard of it and, as a result, read it. But when I just browse the amazon store with no particular aim, I rarely look at who published.
Incidentally Spalding, I just wanted to say I just read your book Life... with no breaks. I absolutely loved it and plan on purchasing Life... on a high once I get through my current list of books to read