I am 99% sure that they are the same textbook content wise. I have seen an older copy of the original Calculus book and it looked identical to a later edition of the Early Transcendentals variety.
Also, it is much more reasonable to look at stewart in comparison to other calculus books using google books than to put all your faith behind Amazon reviewers. Another point that's not often made is that it's definitely worth it to see what calc books are available at the library. There is no compelling reason to buy the book unless there are no renewals allowed (which would be weird). You save a lot of money and if you really want a certain book as a reference later or if you really liked it, then you can buy it, but this can be done later if the book is available at the library.
Many people on these forums will recommend Spivak, myself included, and some will look at a book such as Stewarts with disgust. But most people who encounter Spivak will have seen calculus before, even if this is not the original intent of the author. Just remember that Spivak is as good, if not better than many intro to analysis textbooks, so if you are not at that level yet, there is nothing wrong with starting with Stewart. I would recommend that you go to google books, search for Spivak (the 3rd edition should be online), and try to read chapter 1, chapter 5, or the part right after the last theorem in chapter 7 AND chapter 8 and see how it suits you. If you can get a grasp on what Spivak is talking about in those sections (more precisely, if you can follow his arguments), you can work through the entire book.
