It's a good guide, but slightly outdated. It was based on unpatched version of the game and now that we have the enhanced edition things have slightly changed. For example the best steel sword in chapter 2 is Poisoned Zerrikanian Saberra, which can be bought from mysterious merchant.
You can find all sorts of useful information here:
http://www.gamebanshee.com/thewitcher2/walkthrough.php Good overview of what to look for in each chapter.