Adobe Acrobat is the defacto standard for reading pdf documents. After all, Adobe created the pdf file format. But the product has recently suffered so many security flaws that many security conscious IT pros won't use it. However, sometimes you can't get around the fact that Adobe requires the use of their product to read/use documents created by their products. In other words, their Adobe Creator product embeds proprietary features that make documents unusable with any other reader.